Tag Archives: SRX

JNCIP-SEC – Configuring Juniper Enhanced Web Filtering

Two more weeks left to take the JNCIP-SEC exam, or I will lose my JNCIS-SEC credentials. I have a fully loaded SRX320 cluster (with advanced feature licenses) and a vSRX in place so I need to lab up quickly. First feature on the list is Juniper Enhanced Web filtering.

Before you begin the configuration, make sure you meet the following prerequisites:

  • The device has a valid wf_key_websense_ewf license
  • The egress interface has internet connectivity
  • The device has working name-servers defined
  • If you are enabling the feature on a virtual router, be sure to define the VR under [edit security utm feature-profile web-filtering]

To activate the Juniper Enhanced Web Filtering feature, enter the following command:

[edit security utm feature-profile web-filtering]
root@NP-vSRX# show
type juniper-enhanced;

Next, enable the UTM feature profile for Juniper Enhanced Web Filtering and configure the Juniper-managed Websense server URL.

[edit security utm feature-profile web-filtering]
root@NP-vSRX# show
juniper-enhanced {
    server {
        host rp.cloud.threatseeker.com;
        port 80;
    }
}

Before we configure the Websense categories, we should define custom whitelists and blacklists, which can be used to overrule unexpected results from the automated Websense categorization.

Under the UTM custom-objects, we’ll create an URL pattern for one of our favorite networking-related forums and for a blacklisted adult site. These are then addded to custom black/whitelist categories.

[edit security utm custom-objects]
root@NP-vSRX# show
url-pattern {
    URL-networking-forumsdotcom {
        value [ http://networking-forums.com 64.90.58.116 ];
    }
    URL-sexdotcom {
        value [ sex.com 206.125.164.82 ];
    }
}
custom-url-category {
    EWF-Blacklist {
        value URL-sexdotcom;
    }
    EWF-Whitelist {
        value URL-networking-forumsdotcom;
    }
}

Our two custom URL categories are added under the global web-filtering configuration.

[edit security utm feature-profile web-filtering]
root@NP-vSRX# show
url-whitelist EWF-Whitelist;
url-blacklist EWF-Blacklist;

As for the Enhanced Web-filtering example, I’ll create one profile for standard internet access called “WF-DefaultInternetAccess”. Adult content and malicious URLs/IP addresses will be blocked by default and some ‘undesirable’ categories will be allowed, yet a security event will be logged. The default action will be set to “permit”.

[edit security utm feature-profile web-filtering juniper-enhanced]
root@NP-vSRX# show
cache;
server {
    host rp.cloud.threatseeker.com;
    port 80;
}
profile WF-DefaultInternetAccess {
    category {
        Enhanced_Adult_Content {
            action block;
        }
        Enhanced_Adult_Material {
            action block;
        }
        Enhanced_Advanced_Malware_Command_and_Control {
            action block;
        }
        Enhanced_Advanced_Malware_Payloads {
            action block;
        }
        Enhanced_Bot_Networks {
            action block;
        }
        Enhanced_Dynamic_DNS {
            action block;
        }
        Enhanced_Emerging_Exploits {
            action block;
        }
        Enhanced_Keyloggers {
            action block;
        }
        Enhanced_Malicious_Embedded_Link {
            action block;
        }
        Enhanced_Malicious_Embedded_iFrame {
            action block;
        }
        Enhanced_Malicious_Web_Sites {
            action block;
        }
        Enhanced_Mobile_Malware {
            action block;
        }
        Enhanced_Parked_Domain {
            action block;
        }
        Enhanced_Phishing_and_Other_Frauds {
            action block;
        }
        Enhanced_Proxy_Avoidance {
            action block;
        }
        Enhanced_Spyware {
            action block;
        }
        Enhanced_Abused_Drugs {
            action log-and-permit;
        }
        Enhanced_Alcohol_and_Tobacco {
            action log-and-permit;
        }
        Enhanced_Drugs {
            action log-and-permit;
        }
        Enhanced_Gambling {
            action log-and-permit;
        }
        Enhanced_Games {
            action log-and-permit;
        }
        Enhanced_Hacking {
            action log-and-permit;
        }
        Enhanced_Illegal_or_Questionable {
            action log-and-permit;
        }
        Enhanced_Nudity {
            action log-and-permit;
        }
        Enhanced_Racism_and_Hate {
            action log-and-permit;
        }
        Enhanced_Sex {
            action log-and-permit;
        }
    }
    default permit;
    fallback-settings {
        default log-and-permit;
        server-connectivity block;
        timeout block;
        too-many-requests block;
    }
}

In case a URL does not have a category assigned but only a Web Reputation Score (WBRS) we can define an action based on that score.

Note – the scores are weighted as follows:

  • 100-90–Site is considered very safe.
  • 80-89–Site is considered moderately safe.
  • 70-79–Site is considered fairly safe.
  • 60-69–Site is considered suspicious.
  • 0-59–Site is considered harmful.
[edit security utm feature-profile web-filtering juniper-enhanced profile WF-DefaultInternetAccess site-reputation-action]
root@NP-vSRX# show
very-safe permit;
moderately-safe permit;
fairly-safe log-and-permit;
suspicious quarantine;
harmful block;

For some special cases, in which the device might not be able to process the HTTP request, we can define fallback options. This basically equates to a fail-open/fail-closed decision.

[edit security utm feature-profile web-filtering juniper-enhanced profile WF-DefaultInternetAccess fallback-settings]
root@NP-vSRX# show
default log-and-permit;
server-connectivity block;
timeout block;
too-many-requests block;

With most pieces in place, the full web-filtering profile looks like this:

[edit security utm feature-profile]
root@NP-vSRX# show
web-filtering {
    url-whitelist EWF-Whitelist;
    url-blacklist EWF-Blacklist;
    type juniper-enhanced;
    juniper-enhanced {
        cache;
        server {
            host rp.cloud.threatseeker.com;
            port 80;
        }
        profile WF-DefaultInternetAccess {
            category {
                Enhanced_Adult_Content {
                    action block;
                }
                Enhanced_Adult_Material {
                    action block;
                }
                Enhanced_Advanced_Malware_Command_and_Control {
                    action block;
                }
                Enhanced_Advanced_Malware_Payloads {
                    action block;
                }
                Enhanced_Bot_Networks {
                    action block;
                }
                Enhanced_Dynamic_DNS {
                    action block;
                }
                Enhanced_Emerging_Exploits {
                    action block;
                }
                Enhanced_Keyloggers {
                    action block;
                }
                Enhanced_Malicious_Embedded_Link {
                    action block;
                }
                Enhanced_Malicious_Embedded_iFrame {
                    action block;
                }
                Enhanced_Malicious_Web_Sites {
                    action block;
                }
                Enhanced_Mobile_Malware {
                    action block;
                }
                Enhanced_Parked_Domain {
                    action block;
                }
                Enhanced_Phishing_and_Other_Frauds {
                    action block;
                }
                Enhanced_Proxy_Avoidance {
                    action block;
                }
                Enhanced_Spyware {
                    action block;
                }
                Enhanced_Abused_Drugs {
                    action log-and-permit;
                }
                Enhanced_Alcohol_and_Tobacco {
                    action log-and-permit;
                }
                Enhanced_Drugs {
                    action log-and-permit;
                }
                Enhanced_Gambling {
                    action log-and-permit;
                }
                Enhanced_Games {
                    action log-and-permit;
                }
                Enhanced_Hacking {
                    action log-and-permit;
                }
                Enhanced_Illegal_or_Questionable {
                    action log-and-permit;
                }
                Enhanced_Nudity {
                    action log-and-permit;
                }
                Enhanced_Racism_and_Hate {
                    action log-and-permit;
                }
                Enhanced_Sex {
                    action log-and-permit;
                }
            }
            site-reputation-action {
                very-safe permit;
                moderately-safe permit;
                fairly-safe log-and-permit;
                suspicious quarantine;
                harmful block;
            }
            default permit;
            fallback-settings {
                default log-and-permit;
                server-connectivity block;
                timeout block;
                too-many-requests block;
            }
        }
    }
}

Next, we need configure a new UTM policy which includes the Enhanced Web Filtering feature. This can be combined with other UTM features such as Sophos anti-virus or content filtering.

[edit security utm]
root@NP-vSRX# set utm-policy UTM-DefaultInternetAccess web-filtering http-profile WF-DefaultInternetAccess

The last step is to attach the UTM profile to a security policy by configuring the application-services action.

[edit security policies from-zone internal-np to-zone internal-transit policy FW-Internal-PermitAll]
root@NP-vSRX# show
match {
    source-address any;
    destination-address any;
    application any;
}
then {
    permit {
        application-services {
            utm-policy UTM-DefaultInternetAccess;
        }
    }
}

Configuring logging

To make webfilter troubleshooting easier, configure the following syslog files, or alternatively send them to a syslog server.

[edit system syslog]
root@NP-vSRX# show
file blocked-sites {
    any any;
    match WEBFILTER_URL_BLOCKED;
}
file allowed-sites {
    any any;
    match WEBFILTER_URL_PERMITTED;
}

Testing

Testing the custom blacklist by browsing to sex.com – HTTPS session was broken (based on destination IP) and the browser returned an error.

Oct 13 14:21:14  NP-vSRX RT_UTM: WEBFILTER_URL_BLOCKED: WebFilter: ACTION="URL Blocked" 10.255.1.13(50278)->206.125.164.82(443) CATEGORY="EWF-Blacklist" REASON="BY_BLACK_LIST" PROFILE="WF-DefaultInternetAccess" URL=206.125.164.82 OBJ=/ username N/A roles N/A

Next, we test the URL in the whitelist (which was actually be blocked by Websense). Networking-forums loads fine now and we have this in the log:

Oct 13 14:23:43  NP-vSRX RT_UTM: WEBFILTER_URL_PERMITTED: WebFilter: ACTION="URL Permitted" 10.255.1.13(50303)->64.90.58.116(443) CATEGORY="EWF-Whitelist" REASON="BY_WHITE_LIST" PROFILE="WF-DefaultInternetAccess" URL=64.90.58.116 OBJ=/ username N/A roles N/A

As a last test, we initiate an HTTP session to http://www.penthouse.com
In the browser, we get the following message:

Juniper Networks Firewall has blocked the URL: 10.255.1.13(62175)->64.59.126.214(80) www.penthouse.com/ CATEGORY: Enhanced_Adult_Content REASON: BY_PRE_DEFINED

And in the syslog file, it looks like this:

Oct 13 14:33:29  NP-vSRX RT_UTM: WEBFILTER_URL_BLOCKED: WebFilter: ACTION="URL Blocked" 10.255.1.13(62175)->64.59.126.214(80) CATEGORY="Enhanced_Adult_Content" REASON="BY_PRE_DEFINED" PROFILE="WF-DefaultInternetAccess" URL=www.penthouse.com OBJ=/ username N/A roles N/A

Verification Commands

To check connectivity between your SRX and the Juniper Websense server:

root@NP-vSRX> show security utm web-filtering status
 UTM web-filtering status:
    Server status: Juniper Enhanced using Websense server UP

Web-filtering statistics – this is useful when the service is not working as expected.

root@NP-vSRX> show security utm web-filtering statistics
 UTM web-filtering statistics:
    Total requests:                     17086
    white list hit:                     20
    Black list hit:                     20
    No license permit:                  0
    Queries to server:                  6472
    Server reply permit:                1868
    Server reply block:                 9
    Server reply quarantine:            0
    Server reply quarantine block:      0
    Server reply quarantine permit:     0
    Custom category permit:             0
    Custom category block:              0
    Custom category quarantine:         0
    Custom category qurantine block:    0
    Custom category quarantine permit:  0
    Site reputation permit:             10597
    Site reputation block:              2495
    Site reputation quarantine:         49
    Site reputation quarantine block:   0
    Site reputation quarantine permit:  1170
    Site reputation by Category         0
    Site reputation by Global           14311
    Cache hit permit:                   847
    Cache hit block:                    11
    Cache hit quarantine:               0
    Cache hit quarantine block:         0
    Cache hit quarantine permit:        0
    Safe-search redirect:               0
    Web-filtering sessions in total:    128000
    Web-filtering sessions in use:      2
    Fallback:                       log-and-permit           block
          Default                                 0               0
          Timeout                                 0               0
     Connectivity                                 0               0
Too-many-requests                                 0               0

That’s pretty much all there is to it for a basic EWF setup. There are many more nerdknobs you can tune but I’ll stick to the basics for my JNCIP-SEC studies.

Bear in mind that the URL filter only works for HTTP traffic and most of the web these day is on SSL and using CDN networks, so it’s very hard to get a good match on SSL traffic. This can be solved by using SSL Forward Proxy or relying more on Layer-7 AppID with custom application signatures.

Sources:

Juniper Enhanced Web Filtering feature guide.

IPv6 on Juniper SRX – Prefix Delegation & DHCPv6

I’m currently setting up IPv6 in my own office so I thought it would be worth documenting the configuration I’m adding on my Juniper equipment to make it all work.

I have an internet subscription with a static IPv4 address and also included with it is a /48 static IPv6 prefix. There are two ways I can set it up: static configuration or “semi-automatic” by using Prefix Delegation. This article discusses the latter and in my next post I will document the static configuration, as that’s what I will ultimately be using.

First Things First – Enabling IPv6 Forwarding

Before you can start using IPv6 on the SRX, the device needs to be explicitly configured to forward V6 traffic. This because, by default, the forwarding mode for IPv6 is set to drop. You can verify this on the command line – as shown below, the default forwarding mode for Inet6 traffic is drop:

np@NP-FW01> show security flow status
  Flow forwarding mode:
    Inet forwarding mode: flow based
    Inet6 forwarding mode: drop
    MPLS forwarding mode: drop
    ISO forwarding mode: drop
  Flow trace status
    Flow tracing status: off
  Flow session distribution
    Distribution mode: RR-based
  Flow ipsec performance acceleration: off
  Flow packet ordering
    Ordering mode: Hardware

To activate it, you must change the forwarding mode. There are three modes to choose from: drop (default), flow-based and packet-based.

[edit]
np@NP-FW01# set security forwarding-options family inet6 mode ?
Possible completions:
  drop                 Disable forwarding
  flow-based           Enable flow-based forwarding
  packet-based         Enable packet-based forwarding

I’m using the SRX as a stateful firewall, so I’ll configure flow-based and commit. JunOS will warn you that the change is active only after a device reboot, so I’ll reboot the SRX and continue below.

[edit]
np@NP-FW01# set security forwarding-options family inet6 mode flow-based
[edit]
np@NP-FW01# show | compare
[edit security]
+   forwarding-options {
+       family {
+           inet6 {
+               mode flow-based;
+           }
+       }
+   }
[edit]
np@NP-FW01# commit
warning: You have enabled/disabled inet6 flow.
You must reboot the system for your change to take effect.
If you have deployed a cluster, be sure to reboot all nodes.
commit complete

After the reboot, the forwarding mode is set to flow based and we can start implementing IPv6.

np@NP-FW01> show security flow status
  Flow forwarding mode:
    Inet forwarding mode: flow based
    Inet6 forwarding mode: flow based
    MPLS forwarding mode: drop
    ISO forwarding mode: drop
  Flow trace status
    Flow tracing status: off
  Flow session distribution
    Distribution mode: RR-based
  Flow ipsec performance acceleration: off
  Flow packet ordering
    Ordering mode: Hardware

Configuring IPv6 with Prefix Delegation

Prefix delegation is a simple method to automate the assignment of IPv6 prefixes on subscriber equipment. The CPE (in my case the SRX) informs the upstream router, called the Broadband Network Gateway (BNG) that it wants to use Prefix Delegation. The BNG retrieves the prefix for the subscriber and announces the /48 back to the CPE, after which both sides confirm the prefix allocation. The CPE will then automatically divide the /48 into smaller /64 subnets on the LAN interfaces it has configured for PD Router Advertisements.

If you want to find out exactly how it works, you can find more information in RFC3633

First, we configure the outside interface, pp0.0 in my case. Notice that we are configuring this under family inet6.

The DHCPv6 client is activated on the outside, ISP-facing interface. Some PD-specific configuration is added and we will request the DNS server addresses from the provider.

[edit interfaces pp0 unit 0 family inet6]
np@NP-FW01# show
dhcpv6-client {
    client-type statefull;
    client-ia-type ia-pd;
    rapid-commit;
    client-identifier duid-type duid-ll;
    req-option dns-server;
    retransmission-attempt 0;
}

The LAN interface, in my case ae0.311, on which I will further delegate the prefix, is specified. Showing this separately as it’s important not to miss this one! 🙂

[edit interfaces pp0 unit 0 family inet6]
np@NP-FW01# set dhcpv6-client update-router-advertisement interface ae0.311

The last step is to allow DHCPv6 packets on the security zone inbound traffic. Could be that you need to add it under the interface, if you specified it further down on that level.

[edit security zones security-zone edge-untrust]
np@NP-FW01# set host-inbound-traffic system-services dhcpv6

If you want to use this on the LAN segment, you will also need to enable DHCPv6 on that security zone and interface. I’m using a guest VLAN for testing so I’ll enable it there.

[edit]
np@NP-FW01# set security zones security-zone edge-guest host-inbound-traffic system-services dhcpv6

After a commit, we see that interface ae0.311 now has a public IPv6 address with a /64 mask.

np@NP-FW01> show interfaces terse
Interface               Admin Link Proto    Local                 Remote

 ae0.311                 up    up   inet     192.168.200.1/24
                                   inet6    2a02:1234:420a:1::1/64
                                            fe80::aad0:e501:37d3:2a80/64
...

Notice that the SRX has taken the original /48 prefix and automatically derived a /64 subnet from it for interface ae0.311: 2a02:1234:420a:1::1/64 .

Note – real prefix modified for obvious reasons 🙂

Before we can test reachability, we will need to configure the default route via pp0.0. I’m using routing-instances (VRFs) so I will add it on my external edge instance.

[edit routing-instances VRF-Edge routing-options]
np@NP-FW01# show
rib VRF-Edge.inet6.0 {
    static {
        route ::/0 next-hop pp0.0;
    }
}

With the default route in place, we should be able to ping a public v6 address from this VRF. Below, we are pinging Google DNS, from the interface with Prefix Delegation.

np@NP-FW01> ping 2001:4860:4860::8888 routing-instance VRF-Edge rapid count 10 source 2a02:1234:420a:1::1
PING6(56=40+8+8 bytes) 2a02:1234:420a:1::1 --> 2001:4860:4860::8888
!!!!!!!!!!
--- 2001:4860:4860::8888 ping6 statistics ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max/std-dev = 31.811/32.841/35.861/1.163 ms

Success! This shows that IPv6-PD is working as expected and that the delegated prefix is globally reachable.

After connecting a test machine inside the VLAN, we can confirm that the router advertisements are working as expected. The client has taken the /64 prefix and assigned itself an EUI-64 address.

Ethernet adapter Ethernet:

   Connection-specific DNS Suffix  . : netprobe.guest
   Description . . . . . . . . . . . : Intel(R) Ethernet Connection (4) I219-V
   Physical Address. . . . . . . . . : C8-5B-76-BC-04-6E
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2a02:1234:420a:1:103f:efd8:f2f7:d0cf(Preferred)
   Temporary IPv6 Address. . . . . . : 2a02:1234:420a:1:293c:fd60:c216:8123(Preferred)
   Link-local IPv6 Address . . . . . : fe80::103f:efd8:f2f7:d0cf%14(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.200.13(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : zondag 12 november 2017 15:23:41
   Lease Expires . . . . . . . . . . : maandag 13 november 2017 15:26:16
   Default Gateway . . . . . . . . . : fe80::aad0:e501:37d3:2a80%14
                                       192.168.200.1
   DHCP Server . . . . . . . . . . . : 192.168.200.1
   DHCPv6 IAID . . . . . . . . . . . : 63462262
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-20-35-58-1B-C8-5B-76-BC-04-6E
   DNS Servers . . . . . . . . . . . : 208.67.220.123
                                       208.67.222.123
   NetBIOS over Tcpip. . . . . . . . : Enabled

Now, this part seems to be working fine, but you may notice that the client has not received any IPv6 name servers.
This is because the client uses SLAAC to configure its v6 address based on the Router Advertisements, but it still relies on DHCPv6 to receive any special information such as DNS servers.

To make this work, we need to add a few more bits of configuration to use the SRX as a a DHCPv6 server.

Handing out DNS servers via DHCPv6

First, configure the DHCPv6 pool with the prefix and the DNS server you want to hand out. I’m using Google DNS here.

np@NP-FW01# show routing-instances VRF-Edge access address-assignment
pool vlan311-dhcpv6 {
    family inet6 {
        prefix 2a02:1234:420a:1::/64;
        dhcp-attributes {
            dns-server {
                2001:4860:4860::8888;
                2001:4860:4860::8844;
            }
        }
    }
}

Next, configure the internal DHCPv6 server under system services, referring to the pool you just created – add it under routing-instances if required!

np@NP-FW01# show routing-instances VRF-Edge system services dhcp-local-server
dhcpv6 {
    overrides {
        interface-client-limit 100;
        process-inform {
            pool vlan311-dhcpv6;
        }
    }
    group ipv6 {
        interface ae0.311;
    }
}
group group-vlan311 {
    interface ae0.311;
}

Activate Router Advertisements for your outside interface. It doesn’t seem to work for me without this.

[edit]
np@NP-FW01# show protocols router-advertisement
interface pp0.0;

The following bit controls the Router Advertisements on the delegated interface and activates the O-Flag (Other Information) on the RAs.

[edit interfaces pp0 unit 0 family inet6 dhcpv6-client update-router-advertisement interface ae0.311]
+         other-stateful-configuration;
+         max-advertisement-interval 6;
+         min-advertisement-interval 3;

After adding this configuration, we see the client has now successfully picked up the new DNS settings.

Ethernet adapter Ethernet:

   Connection-specific DNS Suffix  . : netprobe.guest
   Description . . . . . . . . . . . : Intel(R) Ethernet Connection (4) I219-V
   Physical Address. . . . . . . . . : C8-5B-76-BC-04-6E
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2a02:1234:420a:1:103f:efd8:f2f7:d0cf(Preferred)
   Temporary IPv6 Address. . . . . . : 2a02:1234:420a:1:488c:f549:1e67:254c(Preferred)
   Link-local IPv6 Address . . . . . : fe80::103f:efd8:f2f7:d0cf%14(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.200.13(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : zondag 12 november 2017 15:23:41
   Lease Expires . . . . . . . . . . : maandag 13 november 2017 17:08:57
   Default Gateway . . . . . . . . . : fe80::aad0:e501:37d3:2a80%14
                                       192.168.200.1
   DHCP Server . . . . . . . . . . . : 192.168.200.1
   DHCPv6 IAID . . . . . . . . . . . : 63462262
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-20-35-58-1B-C8-5B-76-BC-04-6E
   DNS Servers . . . . . . . . . . . : 2001:4860:4860::8888
                                       2001:4860:4860::8844
                                       208.67.220.123
                                       208.67.222.123
   NetBIOS over Tcpip. . . . . . . . : Enabled

After adding a security policy that allows IPv6 traffic, the client can succesfully communicate over IPv6.

C:\Users\Simon>nslookup - 2001:4860:4860::8888
Default Server:  google-public-dns-a.google.com
Address:  2001:4860:4860::8888

> google.com
Server:  google-public-dns-a.google.com
Address:  2001:4860:4860::8888

Non-authoritative answer:
Name:    google.com
Addresses:  2a00:1450:400e:80b::200e
          172.217.20.110

C:\Users\Simon>ping -6 www.google.com

Pinging www.google.com [2a00:1450:400e:806::2004] with 32 bytes of data:
Reply from 2a00:1450:400e:806::2004: time=30ms
Reply from 2a00:1450:400e:806::2004: time=31ms
Reply from 2a00:1450:400e:806::2004: time=31ms
Reply from 2a00:1450:400e:806::2004: time=30ms

Ping statistics for 2a00:1450:400e:806::2004:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 30ms, Maximum = 31ms, Average = 30ms

Verification Commands

Checking which prefix was allocated to you by the ISP – don’t forget to specify the routing-instance if you are using them.

np@NP-FW01> show dhcpv6 client binding routing-instance VRF-Edge

IP/prefix                       Expires     State      ClientType    Interface       Client DUID
2a02:1234:420a::/48              2590728     BOUND      STATEFUL      pp0.0           LL0x29-a8:d0:e5:d3:2a:47

You can renew the prefix lease this way:

np@NP-FW01> request dhcpv6 client renew routing-instance VRF-Edge interface pp0.0

Displaying the IPv6 neighbours – this is similar to your ARP table in IPv4.

np@NP-FW01> show ipv6 neighbors
IPv6 Address                 Linklayer Address  State       Exp Rtr Secure Interface
2a02:1234:420a:1:488c:f549:1e67:254c
                             c8:5b:76:bc:04:6e  stale       1017 no no      ae0.311
fe80::103f:efd8:f2f7:d0cf    c8:5b:76:bc:04:6e  stale       363 no  no      ae0.311

Statistics for the DHCPv6 server:

np@NP-FW01> show dhcpv6 server statistics routing-instance VRF-Edge
Dhcpv6 Packets dropped:
    Total               0

Messages received:
    DHCPV6_DECLINE             1
    DHCPV6_SOLICIT             6
    DHCPV6_INFORMATION_REQUEST 60
    DHCPV6_RELEASE             0
    DHCPV6_REQUEST             3
    DHCPV6_CONFIRM             0
    DHCPV6_RENEW               0
    DHCPV6_REBIND              0
    DHCPV6_RELAY_FORW          0
    DHCPV6_RELAY_REPL          0

Messages sent:
    DHCPV6_ADVERTISE           4
    DHCPV6_REPLY               8
    DHCPV6_RECONFIGURE         0
    DHCPV6_RELAY_REPL          0

Now, if I was running a fairly simple network with just a few subnets, I would be using Prefix Delegation but I also have a couple of L3 devices behind this firewall. Extending PD all the way down would make it overly complex, so I’ll go for static configuration with OSPFv3 in the next article.

Please let me know in the comments if this configuration did not work for you!

Consistent software versions on dual-partition JunOS devices

Modern Junos devices have dual boot partitions, each with their own copy of the operating system. This ensures that the device will boot if storage or other boot-related issues are detected on the primary boot partition.

However, when you manually update the software, it is only updated on one of the partitions which is then set as the boot partition. The second, original, partition will keep running on the previous version until it is manually updated as well. This might be an advantage if you are testing a new software version and want to quickly roll back to the old one. It could also wreak havoc if you are inadvertently falling back to a pre-historic software version that is missing or not compatible with some of the features you’ve since enabled. If you have found a stable software version, it’s best to keep both partitions in sync. Here’s how to do it…

Identifying a software mismatch

The first hint is given at boot time. Right before the login prompt and banner, the console will alert you of the software version disparity.

kern.securelevel: -1 -> 1
Creating JAIL MFS partition...
JAIL MFS partition created
Boot media /dev/ad0 has dual root support


WARNING: JUNOS versions running on dual partitions are not same


** /dev/ad0s1a
FILE SYSTEM CLEAN; SKIPPING CHECKS
clean, 242154 free (34 frags, 30265 blocks, 0.0% fragmentation)

You can also find out from operational mode. The command below will show you the software versions on both of the partitions.

netprobe@netfilter> show system snapshot media internal
Information for snapshot on       internal (/dev/ad0s1a) (backup)
Creation date: Jul 31 11:13:12 2014
JUNOS version on snapshot:
  junos  : 12.1X44-D35.5-domestic
Information for snapshot on       internal (/dev/ad0s2a) (primary)
Creation date: Mar 4 19:53:11 2016
JUNOS version on snapshot:
  junos  : 12.1X46-D40.2-domestic

As you can see from the output, we are currently running on partition /dev/ad0s2a, which has a newer software version than the first partition /dev/ad0s1a.

Cloning the primary partition

To get the software version from our now-primary partition over to the backup, the system will first format the backup partition and then clone the contents. This process is initiated with the command below.

netprobe@netfilter> request system snapshot slice alternate
Formatting alternate root (/dev/ad0s1a)...
Copying '/dev/ad0s2a' to '/dev/ad0s1a' .. (this may take a few minutes)
The following filesystems were archived: /

After the cloning process you might need to reboot the device, depending on the model. If all went well, you will no longer see the warning prompt for version mismatch:

Creating JAIL MFS partition...
JAIL MFS partition created
Boot media /dev/ad0 has dual root support
** /dev/ad0s1a
FILE SYSTEM CLEAN; SKIPPING CHECKS

And voila, the snapshot command will now show the same SW version on both partitions.

netprobe@netfilter> show system snapshot media internal
Information for snapshot on       internal (/dev/ad0s1a) (backup)
Creation date: Mar 4 21:45:37 2016
JUNOS version on snapshot:
  junos  : 12.1X46-D40.2-domestic
Information for snapshot on       internal (/dev/ad0s2a) (primary)
Creation date: Mar 4 21:48:51 2016
JUNOS version on snapshot:
  junos  : 12.1X46-D40.2-domestic

On EX switches, you can alternate between boot partitions by entering this command.

request system reboot slice alternate media internal

Unfortunately this doesn’t seem to work on SRX devices, at least not on the branch devices I’ve worked with so far. If anyone knows how to make this work on these SRXs I would love to hear about it!

Juniper SRX Clustering with LACP

Most deployment guides for SRX clusters out there focus on standard two-port deployments, where you have one port in, one port out and a couple of cluster links that interconnect and control the cluster. Unfortunately, in that design, one simple link failure will usually make the cluster fail over. Coming from the R&S realm, I am very careful when it comes to physical redundancy so I wanted to figure out a way to get this working with Etherchannels.

After a lot of reading and some trial and error, I ended up with a working solution. Probably not perfect, but definitely more redundant. So, in this post we will get the topology below configured and afterwards do some failover testing.

Physical connections

Basic Cluster Setup

The commands below will get the basic cluster up and running, assuming you have already configured the cluster and node ids.

set system root-authentication encrypted-password "$1$FQl4d.NC$l25c0bDGr5aPq9ZHx0R.S."
set groups node0 system host-name FW01A
set groups node1 system host-name FW01B
set apply-groups "${node}"
set chassis cluster reth-count 2
set chassis cluster redundancy-group 0 node 0 priority 120
set chassis cluster redundancy-group 0 node 1 priority 1
set chassis cluster redundancy-group 1 node 0 priority 120
set chassis cluster redundancy-group 1 node 1 priority 1
set chassis cluster redundancy-group 1 preempt
set interfaces fab0 fabric-options member-interfaces fe-0/0/5
set interfaces fab1 fabric-options member-interfaces fe-1/0/5

Layer3 Etherchannel configuration on the SRX

The physical ports will be bundled in two reth interface. Per reth interface, we will add two physical ports per cluster node, which yields a total of four ports. However only two links will ever be actively forwarding traffic – those on the active RG.

Physical connections

It is important that the links from every cluster nodes are terminated on separate etherchannels on the switches. Otherwise the switches would also load-balance the traffic over the two non-forwarding ports, as documented here…
In my topology, both switches have a Port-Channel 11 and 12, going to their own cluster node.

{primary:node0}
root@FW01A> show configuration interfaces
fe-0/0/0 {
    fastether-options {
        redundant-parent reth0;
    }
}
fe-0/0/1 {
    fastether-options {
        redundant-parent reth0;
    }
}
fe-0/0/2 {
    fastether-options {
        redundant-parent reth1;
    }
}
fe-0/0/3 {
    fastether-options {
        redundant-parent reth1;
    }
}
fe-1/0/0 {
    fastether-options {
        redundant-parent reth0;
    }
}
fe-1/0/1 {
    fastether-options {
        redundant-parent reth0;
    }
}
fe-1/0/2 {
    fastether-options {
        redundant-parent reth1;
    }
}
fe-1/0/3 {
    fastether-options {
        redundant-parent reth1;
    }
}

Pay special attention to the configuration of the reth interfaces. First, we tie the redundant interfaces to our redundancy-group 1, in which we will later control the failover conditions.

The minimum-links command determines how many interfaces must be up before the LACP bundle is considered up. Although we have two interfaces per cluster, we still want traffic forwarded in a worst-case scenario. Setting minimum-links 1 will keep the Etherchannel up even in the unlikely event of having three physical ports down.

reth0 {
    vlan-tagging;
    redundant-ether-options {
        redundancy-group 1;
        minimum-links 1;
        lacp {
            active;
            periodic fast;
        }
    }
    unit 111 {
        vlan-id 111;
        family inet {
            address 1.1.1.1/28;
        }
    }
}
reth1 {
    vlan-tagging;
    redundant-ether-options {
        redundancy-group 1;
        minimum-links 1;
        lacp {
            active;
            periodic fast;
        }
    }
    unit 255 {
        vlan-id 255;
        family inet {
            address 10.255.255.254/28;
        }
    }
}

By adding the vlan-tagging command, and adding a logical subinterface (unit 255) with vlan-id 255 specified, we are creating a tagged L3 Etherchannel. In other words, the SRX is expecting packets for sub-interface reth1.255 to be tagged with a dot1q value of 255. The unit number can be any number you like, but it’s best to keep the unit number and the dot1q value aligned – for your own sanity! 🙂

Security Zones and Policies

To check basic connectivity and later run some failover tests, I have added the following configuration for the Security Zones, Policies and Source NAT. In a production environment, you probably won’t be allowing ping.

root@FW01A# show zones
security-zone trust {
    address-book {
        address Net-10.255.255.240-28 10.255.255.240/28;
    }
    host-inbound-traffic {
        system-services {
            ping;
        }
    }
    interfaces {
        reth1.255;
    }
}
security-zone untrust {
    address-book {
        address Net-1.1.1.0-28 1.1.1.0/28;
    }
    interfaces {
        reth0.111 {
            host-inbound-traffic {
                system-services {
                    ping;
                }
            }
        }
    }
}
{primary:node0}[edit security]
root@FW01A# show policies
from-zone trust to-zone untrust {
    policy Test-Policy {
        match {
            source-address Net-10.255.255.240-28;
            destination-address Net-1.1.1.0-28;
            application any;
        }
        then {
            permit;
        }
    }
}
{primary:node0}[edit security]
root@FW01A# show nat
source {
    rule-set SNAT-Trust-to-Untrust {
        from zone trust;
        to zone untrust;
        rule HideNAT-1 {
            match {
                source-address 10.255.255.240/28;
            }
            then {
                source-nat {
                    interface;
                }
            }
        }
    }
}

Preparing the switches for L2

I’m running two Cisco 3550 switches as my layer3 core switches. For now, I will just add the Layer 1 and 2 stuff.

vlan 111
 name untrust
!
vlan 255
 name transit


interface range fastEthernet 0/1 - 2
 channel-group 11 mode active

interface range fastEthernet 0/3 - 4
 channel-group 12 mode active

int po 11
 switchport trunk encapsulation dot1q
 switchport mode trunk
 switchport nonegotiate
 switchport trunk allowed vlan 111

int po 12
 switchport mode trunk
 switchport nonegotiate
 switchport trunk allowed vlan 255

For CS2, we can copy paste the exact same config.

A second trunk link is added between the core switches, which will carry inter-switch traffic for VLAN 111 and 255.

interface FastEthernet0/23
 channel-group 1 mode active
!
interface FastEthernet0/24
 channel-group 1 mode active

...

interface Port-channel1
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 111,255
 switchport mode trunk
 switchport nonegotiate

The LACP configuration is now complete, and after cabling everything up we see the Port-channels are in the bundled state:

NP-CS1>show etherchannel summary
Flags:  D - down        P - bundled in port-channel
        I - stand-alone s - suspended
        H - Hot-standby (LACP only)
        R - Layer3      S - Layer2
        U - in use      f - failed to allocate aggregator

        M - not in use, minimum links not met
        u - unsuitable for bundling
        w - waiting to be aggregated
        d - default port


Number of channel-groups in use: 3
Number of aggregators:           3

Group  Port-channel  Protocol    Ports
------+-------------+-----------+-----------------------------------------------
1      Po1(SU)         LACP      Fa0/23(P)   Fa0/24(P)
11     Po11(SU)        LACP      Fa0/1(P)    Fa0/2(P)
12     Po12(SU)        LACP      Fa0/3(P)    Fa0/4(P)

The SRX is bit more detailed with the information in the lacp command

root@FW01A> show lacp interfaces
Aggregated interface: reth0
    LACP state:       Role   Exp   Def  Dist  Col  Syn  Aggr  Timeout  Activity
      fe-0/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      fe-0/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Slow    Active
      fe-0/0/1       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      fe-0/0/1     Partner    No    No   Yes  Yes  Yes   Yes     Slow    Active
      fe-1/0/0       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      fe-1/0/0     Partner    No    No   Yes  Yes  Yes   Yes     Slow    Active
      fe-1/0/1       Actor    No    No   Yes  Yes  Yes   Yes     Fast    Active
      fe-1/0/1     Partner    No    No   Yes  Yes  Yes   Yes     Slow    Active
    LACP protocol:        Receive State  Transmit State          Mux State
      fe-0/0/0                  Current   Slow periodic Collecting distributing
      fe-0/0/1                  Current   Slow periodic Collecting distributing
      fe-1/0/0                  Current   Slow periodic Collecting distributing
      fe-1/0/1                  Current   Slow periodic Collecting distributing

Layer3 Switch Configuration

Now that we have our layer 2 connectivity, we can move on to the IP addressing. On the L3 switches, I will configure the SVIs in the transit network, and run HSRP between them with hello/hold timers of 1 and 3 seconds. This would allow for a reasonable failover time in case of an outage.

NP-CS1:

interface Vlan255
 ip address 10.255.255.242 255.255.255.240
 standby 255 ip 10.255.255.241
 standby 255 timers 1 3
 standby 255 priority 110
 standby 255 preempt

NP-CS2:

NP-CS2#sh run int vlan 255
!
interface Vlan255
 ip address 10.255.255.243 255.255.255.240
 standby 255 ip 10.255.255.241
 standby 255 timers 1 3
 standby 255 preempt

The VLAN interfaces come up immediately and as a final test for basic L3 connectivity, we try pinging the SRX from the core switch.

NP-CS1#ping 10.255.255.254 repeat 10

Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 10.255.255.254, timeout is 2 seconds:
!!!!!!!!!!
Success rate is 100 percent (10/10), round-trip min/avg/max = 1/2/4 ms

Checking the ARP table, we can see the Cluster MAC address, with the 4th last digit (1) being the cluster ID and the last two (01) the reth number.

NP-CS1#show ip arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  10.255.255.254          1   0010.dbff.1001  ARPA   Vlan255
Internet  10.255.255.242          -   0012.7f81.8f00  ARPA   Vlan255
Internet  10.255.255.243          8   000d.ed6f.9680  ARPA   Vlan255
Internet  10.255.255.241          -   0000.0c07.acff  ARPA   Vlan255

The default route on both core switches is pointed to 10.255.255.254

ip route 0.0.0.0 0.0.0.0 10.255.255.254

Internet segment configuration

I have connected two routers to the fa0/5 interfaces of the switches and added them to vlan 111. They are running HSRP with a VIP of 1.1.1.14 and hello/hold timers of 1 and 3 seconds.

ISP1#show standby brief
                     P indicates configured to preempt.
                     |
Interface   Grp  Pri P State   Active          Standby         Virtual IP
Fa0/1       111  110   Active  local           1.1.1.13        1.1.1.14

Running a simple ping to test connectivity between the firewalls and the ISP router.

root@FW01A> ping 1.1.1.14 count 1
PING 1.1.1.14 (1.1.1.14): 56 data bytes
64 bytes from 1.1.1.14: icmp_seq=0 ttl=255 time=2.981 ms

*snip*

To test if traffic is being forwarded across the firewall, we finally try reaching the ISP routers from the core switches.

NP-CS1#ping 1.1.1.14 source vlan 255

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.14, timeout is 2 seconds:
Packet sent with a source address of 10.255.255.242
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

After many bits of configuration, our cluster is live so we can start implementing some failover mechanisms.

Configuring the interface-monitor

When the interface-monitor is configured, it sets a threshold value of 255 to each redundancy group. Each interface is assigned a custom weight for the redundancy group, which is detracted from the threshold if the interface goes physically down. When the threshold reaches zero, the redundancy group and all its objects fail over.

Note – a commmon mistake (trust me) is to mix up the interface monitor weights with the RG priorities. These are two separate values, the interface monitor threshold is always 255 by default.

In my lab scenario, I will give each port a value of 128. Two physical links down will trigger a failover to node 1. This is the final configuration for redundancy group 1:

{primary:node0}[edit chassis cluster]
root@FW01A# show
reth-count 2;
redundancy-group 0 {
    node 0 priority 120;
    node 1 priority 1;
}
redundancy-group 1 {
    node 0 priority 120;
    node 1 priority 1;
    preempt;
    interface-monitor {
        fe-0/0/0 weight 128;
        fe-0/0/1 weight 128;
        fe-1/0/0 weight 128;
        fe-1/0/1 weight 128;
        fe-0/0/2 weight 128;
        fe-0/0/3 weight 128;
        fe-1/0/3 weight 128;
        fe-1/0/2 weight 128;
    }

Failover scenarios

  • First, we will physically disconnect fe-0/0/0 which should not impact our regular traffic flow.

Disconnecting fe-0/0/0/

{primary:node0}
root@FW01A> show interfaces terse | match fe-0/0/0
fe-0/0/0                up    down
fe-0/0/0.111            up    down aenet    --> reth0.111
fe-0/0/0.32767          up    down aenet    --> reth0.32767

The JSRPD daemon logged the following entries in which we can see it decrement the value of 128 of the global threshold of 255.

root@FW01A> show log jsrpd | last | match 19:30
Oct  6 19:30:31 Interface fe-0/0/0 is going down
Oct  6 19:30:31 fe-0/0/0 interface monitored by RG-1 changed state from Up to Down
Oct  6 19:30:31 intf failed, computed-weight -128
Oct  6 19:30:31 LED changed from Green to Amber, reason is Monitored objects are down
Oct  6 19:30:31 Current threshold for rg-1 is 127. Failures: interface-monitoring
Oct  6 19:30:42 printing fpc_num h0
Oct  6 19:30:42 jsrpd_ifd_msg_handler: Interface reth0 is up
Oct  6 19:30:42 reth0 from  jsrpd_ssam_reth_read reth_rg_id=1

The chassis cluster interfaces also shows us the interface as down and how much weight it had:

root@FW01A> show chassis cluster interfaces | find Monitoring
Interface Monitoring:
    Interface         Weight    Status    Redundancy-group
    fe-1/0/2          128       Up        1
    fe-1/0/3          128       Up        1
    fe-0/0/3          128       Up        1
    fe-0/0/2          128       Up        1
    fe-1/0/1          128       Up        1
    fe-1/0/0          128       Up        1
    fe-0/0/1          128       Up        1
    fe-0/0/0          128       Down      1

Because our threshold value is still at 127 (255 – 128), RG1 is still active on node0 and no failover event was triggered.

Redundancy group: 1 , Failover count: 0
    node0                   120         primary        yes      no
    node1                   1           secondary      yes      no
  • As a second test, we will also unplug fe-0/0/1. Without the interface monitoring, this would halt the forwarding of traffic to the untrust zone as reth0 would have no more interfaces on node0.

Disconnecting fe-0/0/1 as well

To get a basic idea of the failover time, I’m running a ping test from the core switch.

Sending 1000, 100-byte ICMP Echos to 1.1.1.14, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
*snip*

We lost one packet during the failover with a timeout of two seconds, which is not bad at all. The switchover is stateful so TCP connections should be able to handle this just fine. Let’s see what happened on the SRX…

Our interface monitor shows two interfaces down that had a weight of 128. The threshold should now have reached zero which retired node0 from the cluster.

root@FW01A> show chassis cluster interfaces | find Monitoring
Interface Monitoring:
    Interface         Weight    Status    Redundancy-group
    fe-1/0/2          128       Up        1
    fe-1/0/3          128       Up        1
    fe-0/0/3          128       Up        1
    fe-0/0/2          128       Up        1
    fe-1/0/1          128       Up        1
    fe-1/0/0          128       Up        1
    fe-0/0/1          128       Down      1
    fe-0/0/0          128       Down      1

Redundancy group 1 is now primary on node1. The routing engine is still active on node0.

root@FW01A> show chassis cluster status
Cluster ID: 1
Node                  Priority          Status    Preempt  Manual failover

Redundancy group: 0 , Failover count: 0
    node0                   120         primary        no       no
    node1                   1           secondary      no       no

Redundancy group: 1 , Failover count: 1
    node0                   0           secondary      yes      no
    node1                   1           primary        yes      no

And the JSRPD logged documented the entire event:

Oct  6 19:43:01 Interface fe-0/0/1 is going down
Oct  6 19:43:01 fe-0/0/1 interface monitored by RG-1 changed state from Up to Down
Oct  6 19:43:01 intf failed, computed-weight -256
Oct  6 19:43:01 RG(1) priority changed on node0 120->0 Priority is set to 0, Monitoring objects are down
Oct  6 19:43:01 Successfully sent an snmp-trap due to priority change from 120 to 0 on RG-1 on cluster 1 node 0. Reason: Priority is set to 0, Monitoring objects are down
Oct  6 19:43:01 Current threshold for rg-1 is -1. Setting priority to 0. Failures: interface-monitoring
Oct  6 19:43:01 Both the nodes are primary. RG-1 PRIMARY->SECONDARY_HOLD due to preempt/yield, my priority 0 is worse than other node's priority 1
Oct  6 19:43:01 Successfully sent an snmp-trap due to a failover from primary to secondary-hold on RG-1 on cluster 1 node 0. Reason: Monitor failed: IF
Oct  6 19:43:01 updated rg_info for RG-1 with failover-cnt 1 state: secondary-hold into ssam. Result = success, error: 0
Oct  6 19:43:01 reth0 ifd state changed from node0-primary -> node1-primary for RG-1
Oct  6 19:43:01 reth1 ifd state changed from node0-primary -> node1-primary for RG-1
Oct  6 19:43:01 updating primary-node as node1 for RG-1 into ssam. Previous primary was node0. Result = success, 0
Oct  6 19:43:01 Successfully sent an snmp-trap due to a failover from primary to secondary-hold on RG-1 on cluster 1 node 0. Reason: Monitor failed: IF
Oct  6 19:43:01 printing fpc_num h0
Oct  6 19:43:01 jsrpd_ifd_msg_handler: Interface reth0 is up
Oct  6 19:43:01 reth0 from  jsrpd_ssam_reth_read reth_rg_id=1
Oct  6 19:43:01 printing fpc_num h1
Oct  6 19:43:01 jsrpd_ifd_msg_handler: Interface reth1 is up
Oct  6 19:43:01 reth1 from  jsrpd_ssam_reth_read reth_rg_id=1
Oct  6 19:43:02 SECONDARY_HOLD->SECONDARY due to back to back failover timer expiry for RG-1
Oct  6 19:43:02 Successfully sent an snmp-trap due to a failover from secondary-hold to secondary on RG-1 on cluster 1 node 0. Reason: Back to back failover interval expired
Oct  6 19:43:02 updated rg_info for RG-1 with failover-cnt 1 state: secondary into ssam. Result = success, error: 0
Oct  6 19:43:02 Successfully sent an snmp-trap due to a failover from secondary-hold to secondary on RG-1 on cluster 1 node 0. Reason: Back to back failover interval expired

What is interesting is that the SRX is explicitly sending an SNMP trap for these events, so make sure you have a good monitoring tool and trap receiver in place, preferably with alerting.

  • As the ultimate test, I will unplug interface fe-1/0/0, the first port of node1, which will make the whole LACP bundle reth0 run on just one link. If we had configured minimum-links 2 this action would bring down the whole reth bundle

We are riding on one wheel now!

After pulling the cable, reth0 is strolling along on just one link:

root@FW01A> show lacp interfaces reth0 | find protocol
    LACP protocol:        Receive State  Transmit State          Mux State
      fe-0/0/0            Port disabled     No periodic           Detached
      fe-0/0/1            Port disabled     No periodic           Detached
      fe-1/0/0            Port disabled     No periodic           Detached
      fe-1/0/1                  Current   Slow periodic Collecting distributing

And the Etherchannel is still up:

root@FW01A> show interfaces terse | match reth0
reth0                   up    up
reth0.111               up    up   inet     1.1.1.1/28
reth0.32767             up    up
root@FW01A> show chassis cluster interfaces | find Monitoring
Interface Monitoring:
    Interface         Weight    Status    Redundancy-group
    fe-1/0/2          128       Up        1
    fe-1/0/3          128       Up        1
    fe-0/0/3          128       Up        1
    fe-0/0/2          128       Up        1
    fe-1/0/1          128       Up        1
    fe-1/0/0          128       Down      1
    fe-0/0/1          128       Down      1
    fe-0/0/0          128       Down      1

For anyone designing a network solution with high-availability in mind, this is all very promising. Even with 75% of our physical links down, the reth will stay functional and forward traffic.

I have now reconnected all cabling for a last question I’ve been pondering about – how does the interface monitor react when physical ports go down on both nodes? Suppose we are running our trunks to a chassis or VSS and lose a linecard or stack-member? Does the interface weight count globally and trigger a failover? Let’s find out…

  • Disconnecting fe-0/0/0 and fe-1/0/0, the first port on each node which is in reth0
root@FW01A> show interfaces terse | match "fe-0/0/0|fe-1/0/0"
fe-0/0/0                up    down
fe-0/0/0.111            up    down aenet    --> reth0.111
fe-0/0/0.32767          up    down aenet    --> reth0.32767
fe-1/0/0                up    down
fe-1/0/0.111            up    down aenet    --> reth0.111
fe-1/0/0.32767          up    down aenet    --> reth0.32767

Both links, which both had a weight of 128, are now down but RG1 is still rolling along fine on node0 and the priority is not set to 0. This does prove that the interface-monitor value is tied to the node on which the interface resides.

Redundancy group: 1 , Failover count: 2
    node0                   120         primary        yes      no
    node1                   1           secondary      yes      no

Let’s disconnect fe-0/0/2 and fe-1/0/2 to simulate a really bad day. Our interface monitor now shows half our revenue ports down:

Interface Monitoring:
    Interface         Weight    Status    Redundancy-group
    fe-1/0/2          128       Down      1
    fe-1/0/3          128       Up        1
    fe-0/0/3          128       Up        1
    fe-0/0/2          128       Down      1
    fe-1/0/1          128       Up        1
    fe-1/0/0          128       Down      1
    fe-0/0/1          128       Up        1
    fe-0/0/0          128       Down      1

Interestingly though, both nodes have their priorities now set to zero, but node0 is still primary for RG1.

Redundancy group: 0 , Failover count: 0
    node0                   120         primary        no       no
    node1                   1           secondary      no       no

Redundancy group: 1 , Failover count: 2
    node0                   0           primary        yes      no
    node1                   0           secondary      yes      no

Is there still traffic being sent through though? Running a quick ping from CS2:

NP-CS1#ping 1.1.1.14

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.14, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms

Conclusion

This turned into quite a lengthy post but hopefully demonstrated the benefits of having an Etherchannel over the standard single-port configurations you’ll find in most documentation. Bundling your physical interfaces in a LAG gives you that extra layer of physical redundancy with the added benefit of load sharing on the links. We were able to “lose” 75 percent of our revenue ports without any significant impact. Adding the tagged Layer3 interfaces also gives us the option to add more logical units in the future, which can in turn be assigned to their own routing-instances and zones if you’re dealing with a large-scale or multi-tenant environment.

If this was helpful for you or if you have a remark, please let me know below in the comments! Thanks for reading 🙂

External links that added to my understanding of this topic

Failure is optional – Reth Interfaces and LACP
Juniper KB – Link aggregation (LACP) supported/non-supported configurations on SRX and EX
The free JNCIS-SEC Study Guides at Juniper.net

JNCIS-SEC – Juniper SRX100 Cluster Configuration

In this post I will go through the basics of cluster configuration on the SRX. I still have a couple of SRX100s laying around, which is perfect to cover the clustering topics of the JNCIS-SEC blueprint!

Before you start configuring the cluster, always verify that both your boxes are on the same software version.

root@FW01A> show system software
Information for junos:

Comment:
JUNOS Software Release [12.1X44-D40.2]

Physical Wiring

Here is how the cluster will be cabled up. Because there’s a lot to remember during the configuration, it’s best to make this sort of diagram before you begin.

SRX100B Cluster Wiring

Connect the fxp1 and Fab ports

The Control link (fxp1) is used to synchronize configuration and performs cluster health checks by sending heartbeat messages. The physical port location depends on the SRX model, and can also be configurable on the high-end models. In my case, on the branch SRX100B, the fe0/0/07 interfaces are predetermined as fxp1.

The fab interface is used to exchange all the session state information between both devices. This provides a stateful failover if anything happens to the primary cluster node. You can choose which interface to assign. I will use fe/0/0/5 so all the first ports stay available.

Setting the Cluster-ID and Node ID

First, wipe all the old configuration and put both devices in cluster mode. Some terminology:

  • The cluster ID ranges from 1 to 15 and uniquely identifies the cluster if you have multiple clusters across the network. I will use Cluster ID 1
  • The node ID identifies both members in the cluster. A cluster will only have two members ever, so the options are 0 and 1

The commands below are entered in operational mode:

root@FW01A> set chassis cluster cluster-id 1 node 0 reboot
Successfully enabled chassis cluster. Going to reboot now
root@FW01B> set chassis cluster cluster-id 1 node 1 reboot
Successfully enabled chassis cluster. Going to reboot now

Keep attention when you enter the commands above. Make sure you are actually enabling the cluster, not disabling it. That would return the following message:

 Successfully disabled chassis cluster. Going to reboot now

Configuring the management interfaces

Once the devices have restarted we can move on to the configuration part.

To get out-of-band access to your firewalls, you really should configure both the members with a managment IP on the fxp0 interface.
All member-specific configuration is applied under the groups node-memmbers stanza. This is also where the hostnames are configured.

{primary:node0}[edit groups]
root@FW01A# show
node0 {
    system {
        host-name FW01A;
    }
    interfaces {
        fxp0 {
            unit 0 {
                family inet {
                    address 192.168.1.1/24;
                }
            }
        }
    }
}
node1 {
    system {
        host-name FW01B;
    }
    interfaces {
        fxp0 {
            unit 0 {
                family inet {
                    address 192.168.1.2/24;
                }
            }
        }
    }
}

On the SRX100B, the fxp0 interface is automatically mapped to the fe0/0/6 interface. Be sure to check the documentation for your specific model.

Apply Group

Before committing, don’t forget to include the command below . This ensures that node-specific config is only applied to that particular node.

{primary:node0}[edit]
root@FW01A# set apply-groups "${node}"

Configuring the fabric interface

The next step is to configure your fabric links, which are used to exchange the session state. Node0 has the fab0 interface and Node1 has the fab1 interface.

{primary:node0}[edit interfaces]
root@FW01A# show
fab0 {
    fabric-options {
        member-interfaces {
            fe-0/0/5;
        }
    }
}
fab1 {
    fabric-options {
        member-interfaces {
            fe-1/0/5;
        }
    }
}

After a commit, we can see both the control and fabric links are up.

root@FW01A# run show chassis cluster interfaces
Control link status: Up

Control interfaces:
    Index   Interface        Status
    0       fxp1             Up

Fabric link status: Up

Fabric interfaces:
    Name    Child-interface    Status
                               (Physical/Monitored)
    fab0    fe-0/0/5           Up   / Up
    fab0
    fab1    fe-1/0/5           Up   / Up
    fab1

Redundant-pseudo-interface Information:
    Name         Status      Redundancy-group
    lo0          Up          0

Configuring the Redundancy Groups

The redundancy group is where you configure the cluster’s failover properties relating to a collection of interfaces or other objects. RG0 is configured by default when you activate the cluster, and manages the redundancy for the routing engines. Let’s create a new RG 1 for our interfaces.

{secondary:node0}[edit chassis]
root@FW01A# show
cluster {
    redundancy-group 0 {
        node 0 priority 100;
        node 1 priority 1;
    }
    redundancy-group 1 {
        node 0 priority 100;
        node 1 priority 1;
    }
}

Configuring Redundant Ethernet interfaces

The reth interfaces are bundles of physical ports across both cluster members. The child interfaces inherit the configuration from the overlying reth interface – think of it as being similar to an 802.3ad Etherchannel. In fact, you can use an Etherchannel to use more than one physical port on each node.

{secondary:node0}[edit chassis cluster]
root@FW01A# set reth-count 2

After entering this command, you can do a quick commit, which will make the reth interfaces visible in the terse command.

root@FW01A# run show interfaces terse | match reth
reth0                   up    down
reth1                   up    down

Now you can configure the reth interfaces as you would with any other interface, give them an IP and assign them to the Redundancy Group.

reth0 is our outside interface, and reth1 is the inside.

{secondary:node0}[edit interfaces]
root@FW01A# show reth0
redundant-ether-options {
    redundancy-group 1;
}
unit 0 {
    family inet {
        address 1.1.1.1/24;
    }
}
{secondary:node0}[edit interfaces]
root@FW01A# show reth1
redundant-ether-options {
    redundancy-group 1;
}
unit 0 {
    family inet {
        address 10.0.0.1/24;
    }
}

When our reths are configured, we can add our physical ports. The fe-0/0/0 (node0) and fe-1/0/0 (node1) will join reth0, fe-0/0/1 and fe-1/0/1 will join reth1.

{secondary:node0}[edit interfaces]
root@FW01A# show
fe-0/0/0 {
    fastether-options {
        redundant-parent reth0;
    }
}
fe-0/0/1 {
    fastether-options {
        redundant-parent reth1;
    }
}
fe-1/0/0 {
    fastether-options {
        redundant-parent reth0;
    }
}
fe-1/0/1 {
    fastether-options {
        redundant-parent reth1;
    }
}

Interface monitoring

We can use interface monitoring to subtract a predetermined priority value off our redundancy group priority, when a link goes physically down.

For example, node0 is primary for RG1 with a priority of 100. If we add an interface-monitor value of anything higher than 100 to the physical interface, the link-down event will cause to priority to drop to zero and trigger the failover. Configuration is applied at the redundancy-groups:

{primary:node0}[edit chassis cluster]
root@FW01A# show
reth-count 2;
redundancy-group 0 {
    node 0 priority 100;
    node 1 priority 1;
}
redundancy-group 1 {
    node 0 priority 100;
    node 1 priority 1;
    preempt;
    gratuitous-arp-count 5;
    interface-monitor {
        fe-0/0/0 weight 255;
        fe-0/0/1 weight 255;
        fe-1/0/0 weight 255;
        fe-1/0/1 weight 255;
    }
}

Finally, we add the interfaces to security zones.

root@FW01A# show security zones
security-zone untrust {
    interfaces {
        reth0.0;
    }
}
security-zone trust {
    host-inbound-traffic {
        system-services {
            ping;
        }
    }
    interfaces {
        reth1.0;
    }
}

Verification

After cabling it up, we can verify that the cluster is fully operational.

root@FW01A> show chassis cluster status
Cluster ID: 1
Node                  Priority          Status    Preempt  Manual failover

Redundancy group: 0 , Failover count: 0
    node0                   100         primary        no       no
    node1                   1           secondary      no       no

Redundancy group: 1 , Failover count: 0
    node0                   100         primary        yes      no
    node1                   1           secondary      yes      no
root@FW01A> show chassis cluster interfaces
Control link status: Up

Control interfaces:
    Index   Interface        Status
    0       fxp1             Up

Fabric link status: Up

Fabric interfaces:
    Name    Child-interface    Status
                               (Physical/Monitored)
    fab0    fe-0/0/5           Up   / Up
    fab0
    fab1    fe-1/0/5           Up   / Up
    fab1

Redundant-ethernet Information:
    Name         Status      Redundancy-group
    reth0        Up          1
    reth1        Up          1

Redundant-pseudo-interface Information:
    Name         Status      Redundancy-group
    lo0          Up          0

Interface Monitoring:
    Interface         Weight    Status    Redundancy-group
    fe-1/0/1          255       Up        1
    fe-1/0/0          255       Up        1
    fe-0/0/1          255       Up        1
    fe-0/0/0          255       Up        1

Let’s see how long the failover takes, by unplugging one of the links in the trust zone.

Pinging from the inside switch to the reth1 address 10.0.0.1

theswitch#ping 10.0.0.1 repeat 10000

Type escape sequence to abort.
Sending 10000, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Excellent, only lost one ping while failing over to node1 which would be 2 seconds.

We can see that node1 is now the primary for redundancy group 1, which holds our interfaces:

root@FW01A> show chassis cluster status redundancy-group 1
Cluster ID: 1
Node                  Priority          Status    Preempt  Manual failover

Redundancy group: 1 , Failover count: 3
    node0                   0           secondary      yes      no
    node1                   1           primary        yes      no

{primary:node0}

In the next article, I will dive a bit deeper and integrate the SRX cluster in a real-world topology.

JNCIS-SEC – Custom IDP policies on the Juniper SRX

Activating Intrusion Detection and Prevention (or IPS, as all the cool kids call it) on the SRX is quite straightforward in itself, but turning it on and relying solely on the default IDP policies is not going to cut it. While doing my own tests, running some scriptkiddie attacks against a virtual machine, I was expecting lots of sirens but unfortunately, the SRX stayed silent. No detection and definitely no prevention. As I quickly gathered, you actually need to put some thought in the services you are exposing and the kind of attacks you can expect, and then craft your own policies with the specific signatures.

For this one, I’ll be creating a custom IDP rule on the vSRX. I’m assuming you have already set up the vSRX, activated the advanced features license and set up IDP. If not, here are some links that will put you on the right path.

Scenario

  • We are hosting an SSH/SFTP server on my public IP address of 1.1.1.10/32. Every day, there are hundreds of brute-force login attempts. Obviously, the server admin has not implemented protective measures so we will try to reduce the impact by enabling IDP.
  • Destination NAT has been configured and is translating 1.1.1.10 to internal DMZ server 10.0.4.10.

Here is the firewall configuration. IDP has already been enabled on this policy.

[edit security policies from-zone untrust to-zone dmz policy FW-SFTP-Servers]
root@NP-vSRX-01# show
match {
    source-address any;
    destination-address Grp-SFTP-Servers;
    application junos-ssh;
}
then {
    permit {
        application-services {
            idp;
        }
    }
    log {
        session-init;
    }
}

Server setup and brute-force script

I’m using this script which runs a txt file of common passwords against the username specified.

On the linux server, let’s create a user, aptly named “admin”, with one of the passwords from the text files

lab@V104-10:~$ sudo useradd admin
lab@V104-10:~$ sudo passwd admin
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

First, running the script with the standard IDP policy of Server-Protection-1G

lab@V120-10:/tmp/brutessh$ python brutessh.py -h 1.1.1.10 -u admin -d passlist.txt

*************************************
*SSH Bruteforcer Ver. 0.2           *
*Coded by Christian Martorella      *
*Edge-Security Research             *
*laramies@gmail.com                 *
*************************************

HOST: 1.1.1.10 Username: admin Password file: passlist.txt
===========================================================================
Trying password...
miller


Auth OK ---> Password Found: changeme
tiger

Times -- > Init: 0.032772 End: 6.861204

The SRX was not paying attention during the attack -nothing in the attack table- and the server got owned.

root@NP-vSRX-01> show security idp attack table
root@NP-vSRX-01>

Rolling your own IDP rules

Unfortunately, the server guy had to be let go and we are now looking for a way to be prevent these kinds of attacks. Of course, the first thing to do would be to harden the server and enforce strong credentials, but it does help if you are notified of an ongoing attack. Even better if the SRX could also prevent or slow down the attack.

For our scenario, we are specifically looking for SSH Brute-force attacks. A good way to find out if the SRX has an on-board signature for this is to browse the attack database. You can find all these signatures in operational mode.

root@NP-vSRX-01# run show security idp attack description SSH?
Possible completions:
          Attack name
  SSH:AUDIT:SSH-V1
  SSH:AUDIT:UNEXPECTED-HEADER
  SSH:BRUTE-LOGIN
  SSH:ERROR:COOKIE-MISMATCH
  SSH:ERROR:INVALID-HEADER
  SSH:ERROR:INVALID-PKT-TYPE
  SSH:ERROR:MSG-TOO-LONG
  SSH:ERROR:MSG-TOO-SHORT
  SSH:MISC:EXPLOIT-CMDS-UNIX
  SSH:MISC:MAL-VERSION
  SSH:MISC:UNIX-ID-RESP
  SSH:NON-STD-PORT
  SSH:OPENSSH-MAXSTARTUP-DOS
  SSH:OPENSSH:BLOCK-DOS
  SSH:OPENSSH:GOODTECH-SFTP-BOF
  SSH:OPENSSH:NOVEL-NETWARE
  SSH:OVERFLOW:FREESSHD-KEY-OF
  SSH:OVERFLOW:PUTTY-VER
  SSH:OVERFLOW:SECURECRT-BOF
  SSH:PRAGMAFORT-KEY-OF
  SSH:SYSAX-MULTI-SERVER-DOS
  SSH:SYSAX-SERVER-DOS

root@NP-vSRX-01# run show security idp attack description SSH:BRUTE-LOGIN
Description: This signature detects attempts by remote attackers to log in to an SSH server by brute-forcing the password.

Another great resource for finding the right signature is this page.

If you are using one of the predefined IDP policy sets, navigate down and edit the configuration. I am using Server-Protection-1G on mine.

The policy below will detect SSH brute-force attempts and, by using the ip-action, block the source IP for 30 minutes. That should slow ’em down.

[edit security idp idp-policy Server-Protection-1G rulebase-ips]
root@NP-vSRX-01# show rule SSH-SFTP-Services
match {
    from-zone any;
    source-address any;
    to-zone any;
    destination-address any;
    application default;
    attacks {
        predefined-attacks SSH:BRUTE-LOGIN;
    }
}
then {
    action {
        close-client;
    }
    ip-action {
        ip-block;
        target source-address;
        timeout 1800;
    }
    notification {
        log-attacks;
    }
}

You can rearrange the rules by using the insert policy before

Testing the policy

Running the script for a second time, it only took a small number of brute-force attempts until the alarm triggered. After a minute or two of time-outs, the script gave up and started spawning python errors.

lab@V120-10:/tmp/brutessh$ python brutessh.py -h 1.1.1.10 -u admin -d passlist.txt

*************************************
*SSH Bruteforcer Ver. 0.2           *
*Coded by Christian Martorella      *
*Edge-Security Research             *
*laramies@gmail.com                 *
*************************************

HOST: 1.1.1.10 Username: admin Password file: passlist.txt
===========================================================================
Trying password...
abc123
Exception in thread carmen
:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "brutessh.py", line 44, in run
    t = paramiko.Transport(hostname)
  File "/tmp/brutessh/paramiko/transport.py", line 235, in __init__
    sock.connect((hostname, port))
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
error: [Errno 110] Connection timed out
Exception in thread test
:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "brutessh.py", line 44, in run
    t = paramiko.Transport(hostname)
  File "/tmp/brutessh/paramiko/transport.py", line 235, in __init__
    sock.connect((hostname, port))
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
error: [Errno 110] Connection timed out
Exception in thread password1
:

Some verification commands on the SRX itself.

root@NP-vSRX-01> show security log | match IDP:
2015-09-17 19:22:45 UTC  IDP: at 1442517764, SIG Attack log <2.2.2.1/6768->1.1.1.10/22> for TCP protocol and service SERVICE_IDP application NONE by rule 6 of rulebase IPS in policy Server-Protection-1G. attack: repeat=0, action=CLOSE_CLIENT, threat-severity=MEDIUM, name=SSH:BRUTE-LOGIN, NAT <0.0.0.0:0->10.0.4.10:0>, time-elapsed=0, inbytes=0, outbytes=0, inpackets=0, outpackets=0, intf:untrust:ge-0/0/0.0->dmz:ge-0/0/2.0, packet-log-id: 0, alert=no, username=N/A, roles=N/A and misc-message -

The SRX detected three login attempts through before shunning the remote IP

root@NP-vSRX-01> show security idp attack table
IDP attack statistics:

  Attack name                                  #Hits
  SSH:BRUTE-LOGIN                              3
root@NP-vSRX-01> show security idp attack detail SSH:BRUTE-LOGIN
Display Name: SSH: Brute Force Login Attempt
Severity: Minor
Category: SSH
Recommended: true
Recommended Action: Drop
Type: signature
Direction: CTS
False Positives: rarely
Service: SSH
Shellcode: no
Flow: control
Context: first-data-packet
Negate: false
TimeBinding:
        Scope: peer
        Count: 10
Hidden Pattern: False
Pattern: \[SSH\].*
root@NP-vSRX-01> show security idp counters action
IDP counters:

  IDP counter type                                                      Value
 None                                                                    0
 Recommended                                                             0
 Ignore                                                                  0
 Diffserv                                                                0
 Drop packet                                                             0
 Drop                                                                    0
 Close                                                                   0
 Close server                                                            0
 Close client                                                            3
 IP action rate limit                                                    0
 IP action drop                                                          3
 IP action close                                                         0
 IP action nofity                                                        0
 IP action failed                                                        0

Wrapping up

Although very basic, this example demonstrated that it absolutely pays off to invest some time in crafting your own IDP rules. Keeping a detailed inventory of the services you are hosting and matching it against the associated application-level attack signatures will greatly increase your security posture. Combined with the Screen Options, which protect against some of the L3/L4 attacks, this makes the SRX well worth considering 🙂

Route-based IPsec tunnels on the SRX

Expanding on the basic branch setup from my previous labs, I added another virtual SRX to the topology to exercise the VPN stuff. As the “ISP” router, I first tried adding a CSR-1000V to the lab but found out the hard way that it’s bandwidth throttled at 100kbps. With six virtual machines behind it sporadically fetching stuff off the internet, the entire lab came to a grinding halt. 🙂

As a quick workaround, I settled on a VyOS appliance , which was surprisingly easy to work with. It’s very similar to JunOS so I had it up and running in just a couple of minutes.

Anyway, enough about that. Here’s the network I’ll be working off to build some VPNs…

Topology

VPN Topology

Before you configure VPN tunnels, make sure that your public interface is listening for IKE traffic. This is defined on the zone or interface level.

[edit security zones security-zone untrust]
root@NP-vSRX-01# show
host-inbound-traffic {
    system-services {
        ssh;
        ping;
        ike;
    }
}
interfaces {
    ge-0/0/0.0;
}

Tunnel interface, routing and security zone

First, define a Secure Tunnel interface with IPv4 support by adding the inet family. If you forget the family inet statement, your tunnel will not pass traffic.

For simple tunnels without dynamic routing protocols, assigning an IP address is not required.

[edit interfaces]
root@NP-vSRX-01# show st0
unit 1 {
    description "Branch1 Tunnel Interface";
    family inet;
}

Create a static route for the peer subnet(s) and point it to the tunnel interface.

[edit]
root@NP-vSRX-01# set routing-options static route 10.2.0.0/24 next-hop st0.1

One thing I tend to forget is to add the st0 interface to the right security zone. Rather than putting it in the untrust zone, I will create a separate zone for VPN and put the tunnel there.

[edit security zones security-zone vpn]
root@NP-vSRX-01# show
interfaces {
    st0.1;
}

Once that is done, we can start configuring the actual VPN policy. There are a lot of components to configure, but once you know how they intertwine it’s pretty straightforward.

Configuring Phase 1

First, configure an IKE proposal. You could choose one of the JunOS templates, but where’s the fun in that, right? 🙂

[edit security ike]
root@NP-vSRX-01# show
proposal P1-Proposal-Branch1 {
    description "Branch1 Phase1 Proposal";
    authentication-method pre-shared-keys;
    authentication-algorithm sha-256;
    encryption-algorithm aes-256-cbc;
    lifetime-seconds 43200;
}

Once we have the P1 proposal, we define the phase 1 policy which in turn refers to the proposal. Unless your peer has a dynamic IP, main mode is what you need. This is also where you specify the preshared key.

[edit security ike policy P1-Policy-Branch1]
root@NP-vSRX-01# show
mode main;
description "Branch1 Phase1 Policy";
proposals P1-Proposal-Branch1;
pre-shared-key ascii-text "$9$DDH.f9CuB1hqMORhcle4aZGjq"; ## SECRET-DATA

Third and last for Phase 1 template, configure the gateway peer IP address with the corresponding policy. If possible, always use IKE version 2. The external interface is where the SRX can expect the UDP/500 packets.

[edit security ike gateway P1-Peer-Branch1]
root@NP-vSRX-01# show
ike-policy P1-Policy-Branch1;
address 2.2.2.1;
external-interface ge-0/0/0;
version v2-only;

Now that Phase1 is set, we can move on to the IPsec configuration.

Phase 2 – IPsec

Just as we did before, we first define a proposal. Choose your most secure option for encryption and hashing, and a reasonably short keying lifetime.

[edit security ipsec proposal P2-Proposal-Branch1]
root@NP-vSRX-01# show
description "Branch1 Phase2 Proposal";
protocol esp;
authentication-algorithm hmac-sha-256-128;
encryption-algorithm aes-256-cbc;
lifetime-seconds 3600;

Configure the IPsec policy that again refers to the proposal. Unless the peer does not support it, always turn on PFS.

[edit security ipsec policy P2-Policy-Branch1]
root@NP-vSRX-01# show
description "Branch1 Phase2 Policy";
perfect-forward-secrecy {
    keys group5;
}
proposals P2-Proposal-Branch1;

The final step is where the Phase 1 and 2 components are glued together. For route-based tunnels, don’t forget to bind your st interface. I prefer to negotiate the tunnels immediately rather than waiting for traffic.

[edit security ipsec vpn P2-IPsec-Branch1]
root@NP-vSRX-01# show
bind-interface st0.1;
ike {
    gateway P1-Peer-Branch1;
    ipsec-policy P2-Policy-Branch1;
}
establish-tunnels immediately;

Security Policies

From a VPN point of view, we are ready to accept IPsec connections on this box. We are listening for IKE traffic, we have a route pointing to our tunnel interface and VPN policies are configured. The only thing we need to do is configure the firewall policies.

For this one, I will be allowing traffic from the remote sites to one of the machines on the trust zone. I already created some objects in the global address book.

From VPN to Trust:

[edit security policies from-zone vpn to-zone trust]
root@NP-vSRX-01# show
policy FW-Allow-VPN-Branch {
    match {
        source-address Host-10.2.0.10;
        destination-address Host-10.0.0.10;
        application any;
    }
    then {
        permit;
        count;
    }
}

From Trust to VPN:

[edit security policies]
root@NP-vSRX-01# show from-zone trust to-zone vpn
policy FW-Allow-VPN-Branch {
    match {
        source-address Host-10.0.0.10;
        destination-address Host-10.2.0.10;
        application any;
    }
    then {
        permit;
        count;
    }
}

Configuring the Branch site SRX

The benefit of having two SRX’s is that you can easily copy-paste, edit and mirror the config.

### PHASE 1 ### 

set security ike proposal P1-Proposal-HQ description "HQ Phase1 Proposal"
set security ike proposal P1-Proposal-HQ authentication-method pre-shared-keys
set security ike proposal P1-Proposal-HQ authentication-algorithm sha-256
set security ike proposal P1-Proposal-HQ encryption-algorithm aes-256-cbc
set security ike proposal P1-Proposal-HQ lifetime-seconds 43200
set security ike policy P1-Policy-HQ mode main
set security ike policy P1-Policy-HQ description "HQ Phase1 Policy"
set security ike policy P1-Policy-HQ proposals P1-Proposal-HQ
set security ike policy P1-Policy-HQ pre-shared-key ascii-text "$9$DDH.f9CuB1hqmORhcle4aZGjq"
set security ike gateway P1-Peer-HQ ike-policy P1-Policy-HQ
set security ike gateway P1-Peer-HQ address 1.1.1.1
set security ike gateway P1-Peer-HQ external-interface ge-0/0/0

### PHASE 2 ####

set security ipsec proposal P2-Proposal-HQ description "HQ Phase2 Proposal"
set security ipsec proposal P2-Proposal-HQ protocol esp
set security ipsec proposal P2-Proposal-HQ authentication-algorithm hmac-sha-256-128
set security ipsec proposal P2-Proposal-HQ encryption-algorithm aes-256-cbc
set security ipsec proposal P2-Proposal-HQ lifetime-seconds 3600
set security ipsec policy P2-Policy-HQ description "HQ Phase2 Policy"
set security ipsec policy P2-Policy-HQ perfect-forward-secrecy keys group5
set security ipsec policy P2-Policy-HQ proposals P2-Proposal-HQ
set security ipsec vpn P2-IPsec-HQ bind-interface st0.1
set security ipsec vpn P2-IPsec-HQ ike gateway P1-Peer-HQ
set security ipsec vpn P2-IPsec-HQ ike ipsec-policy P2-Policy-HQ

#### TUNNEL INTERFACE ### 

set interfaces st0 unit 1 description "HQ Tunnel Interface"
set interfaces st0 unit 1 family inet

### HOST INBOUND TRAFFIC ### 

set security zones security-zone untrust host-inbound-traffic system-services ike

### ADD TUNNEL TO ZONE ###

set security zones security-zone untrust interfaces st0.1

### ADD ROUTE ###

set routing-options static route 10.0.0.0/24 next-hop st0.1
set routing-options static route 10.0.4.0/24 next-hop st0.1

### SECURITY POLICIES ### 

set security policies from-zone vpn to-zone branch policy FW-Allow-VPN-HQ-In match source-address Host-10.0.0.10
set security policies from-zone vpn to-zone branch policy FW-Allow-VPN-HQ-In match destination-address Host-10.2.0.10
set security policies from-zone vpn to-zone branch policy FW-Allow-VPN-HQ-In match application any
set security policies from-zone vpn to-zone branch policy FW-Allow-VPN-HQ-In then permit
set security policies from-zone vpn to-zone branch policy FW-Allow-VPN-HQ-In then count
set security policies from-zone branch to-zone vpn policy FW-Allow-VPN-HQ-Server match source-address Host-10.2.0.10
set security policies from-zone branch to-zone vpn policy FW-Allow-VPN-HQ-Server match destination-address Host-10.0.0.10
set security policies from-zone branch to-zone vpn policy FW-Allow-VPN-HQ-Server match application any
set security policies from-zone branch to-zone vpn policy FW-Allow-VPN-HQ-Server then permit
set security policies from-zone branch to-zone vpn policy FW-Allow-VPN-HQ-Server then count

Verification

On the HQ SRX, we already have a phase 1 tunnel up using IKEv2 as the exchange protocol.

root@NP-vSRX-01> show security ike security-associations
Index   State  Initiator cookie  Responder cookie  Mode           Remote Address
2441630 UP     2fb27eba88550b6b  e8b7c6a94c94f8d2  IKEv2          2.2.2.1

We also have a Phase 2 tunnel, with just under one hour of lifetime left.

root@NP-vSRX-01> show security ipsec security-associations
  Total active tunnels: 1
  ID    Algorithm       SPI      Life:sec/kb  Mon lsys Port  Gateway
  <131073 ESP:aes-cbc-256/sha256 14b32bcb 3433/ unlim - root 500 2.2.2.1
  >131073 ESP:aes-cbc-256/sha256 fef69f20 3433/ unlim - root 500 2.2.2.1

Some more details about the IPsec parameters, like Proxy IDs (0.0.0.0/0) and encryption/authentication standards.

root@NP-vSRX-01> show security ipsec security-associations index 131073 detail
  ID: 131073 Virtual-system: root, VPN Name: P2-IPsec-Branch1
  Local Gateway: 1.1.1.1, Remote Gateway: 2.2.2.1
  Local Identity: ipv4_subnet(any:0,[0..7]=0.0.0.0/0)
  Remote Identity: ipv4_subnet(any:0,[0..7]=0.0.0.0/0)
  Version: IKEv2
    DF-bit: clear
    Bind-interface: st0.1

  Port: 500, Nego#: 32, Fail#: 0, Def-Del#: 0 Flag: 0x600a29
  Last Tunnel Down Reason: Delete payload received
    Direction: inbound, SPI: 14b32bcb, AUX-SPI: 0
                              , VPN Monitoring: -
    Hard lifetime: Expires in 3339 seconds
    Lifesize Remaining:  Unlimited
    Soft lifetime: Expires in 2752 seconds
    Mode: Tunnel(0 0), Type: dynamic, State: installed
    Protocol: ESP, Authentication: hmac-sha256-128, Encryption: aes-cbc (256 bits)
    Anti-replay service: counter-based enabled, Replay window size: 64

    Direction: outbound, SPI: fef69f20, AUX-SPI: 0
                              , VPN Monitoring: -
    Hard lifetime: Expires in 3339 seconds
    Lifesize Remaining:  Unlimited
    Soft lifetime: Expires in 2752 seconds
    Mode: Tunnel(0 0), Type: dynamic, State: installed
    Protocol: ESP, Authentication: hmac-sha256-128, Encryption: aes-cbc (256 bits)
    Anti-replay service: counter-based enabled, Replay window size: 64

A good way to verify that there’s two-way communication is to inspect the IPsec counters

root@NP-vSRX-01> show security ipsec statistics index 131073
ESP Statistics:
  Encrypted bytes:        140965904
  Decrypted bytes:       3342178434
  Encrypted packets:        1132200
  Decrypted packets:        2245688
AH Statistics:
  Input bytes:                    0
  Output bytes:                   0
  Input packets:                  0
  Output packets:                 0
Errors:
  AH authentication failures: 0, Replay errors: 251
  ESP authentication failures: 0, ESP decryption failures: 0
  Bad headers: 0, Bad trailers: 0

The ultimate test is to verify on the internal machines. Note the asterisks on the tunnel segment. If there’s an address assigned to the st interface, this one would show in the trace results.

root@Branch-vSRX-01> ssh lab@10.2.0.10
lab@10.2.0.10's password:
Welcome to Ubuntu 14.10 (GNU/Linux 3.16.0-23-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

Last login: Thu Sep 10 22:27:33 2015
lab@V120-10:~$ ping 10.0.0.10
PING 10.0.0.10 (10.0.0.10) 56(84) bytes of data.
64 bytes from 10.0.0.10: icmp_seq=1 ttl=62 time=10.3 ms
64 bytes from 10.0.0.10: icmp_seq=2 ttl=62 time=13.5 ms
64 bytes from 10.0.0.10: icmp_seq=3 ttl=62 time=11.6 ms
^C
--- 10.0.0.10 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 10.370/11.869/13.567/1.318 ms

lab@V120-10:~$ traceroute 10.0.0.10
traceroute to 10.0.0.10 (10.0.0.10), 30 hops max, 60 byte packets
 1  10.2.0.1 (10.2.0.1)  3.864 ms  3.912 ms  4.003 ms
 2  * * *
 3  10.0.0.10 (10.0.0.10)  13.682 ms  13.679 ms  13.666 ms
lab@V120-10:~$

That’s it, a fully functional, although very basic, route-based VPN.

JNCIS-SEC – SRX Static NAT Configuration

I already went into source and destination NAT in the last few posts. The last one I wanted to lab up is Static NAT, which creates a one-to-one mapping between two addresses. The translation is bidirectional and ports are not translated. On the downside, it does require you to sacrifice one public IP per internal server which is not always the most cost-efficient method.

Here’s what I’ll be working on:

SRX NAT topology

The following Static NAT entries will be configured:

  • Server 10.0.100.10 will be translated to 1.1.1.10
  • Server 10.0.100.11 will be translated to 1.1.1.11

Using the Global Address Book

Instead of using regular IP prefixes as matching conditions, I will be using address book entries in the NAT config. Referring to the same names in both security policy and NAT makes interpreting and troubleshooting the config much more straightforward.

First, navigate over to the global address book under Security, and enter addresses as you would under the zones. I am creating objects for both the public and private addresses:

[edit security address-book global]
root@NP-vSRX-01# show
address Host-Private-10.0.100.10 10.0.100.10/32;
address Host-Private-10.0.100.11 10.0.100.11/32;
address Host-Public-1.1.1.10 1.1.1.10/32;
address Host-Public-1.1.1.11 1.1.1.11/32;

Caution, when you start adding entries to the global address book, the SRX will start spawning this error when trying a commit:

[edit security zones security-zone untrust]
root@NP-vSRX-01# show
##
## Warning: Zone specific address books are not allowed when there are global address books defined
##

From the looks of it, you will need to move all your zone address books over to the global one, so make sure you start off right on a new SRX. Worst case, you can still match on regular IP prefixes for NAT.

Next will be to define a ruleset, and create some rules. One thing to keep in mind is that you configure the NAT rule to match on the destination address to perform the NAT. Implicitly, the SRX will then create a reverse source-NAT mapping. Just imagine the traffic entering your network, and to what address it should be translated, and the SRX will take care of the reverse traffic for you.

Here is the configuration for the first host, referencing the object name by using destination-address-name:

[edit security nat static]
root@NP-vSRX-01# show
rule-set Static-From-Untrust {
    from zone untrust;
    rule NAT-DMZ-10 {
        match {
            destination-address-name Host-Public-1.1.1.10;
        }
        then {
            static-nat {
                prefix-name {
                    Host-Private-10.0.100.10;
                }
            }
        }
    }
}

Copy paste for the second host:

rule NAT-DMZ-11 {
    match {
        destination-address-name Host-Public-1.1.1.11;
    }
    then {
        static-nat {
            prefix-name {
                Host-Private-10.0.100.11;
            }
        }
    }
}

Verification

The most useful command for Static NAT verification is show security nat static rule, which shows you both a config overview and a hit count.

root@NP-vSRX-01> show security nat static rule all
Total static-nat rules: 2
Total referenced IPv4/IPv6 ip-prefixes: 4/0

Static NAT rule: NAT-DMZ-10           Rule-set: Static-From-Untrust
  Rule-Id                    : 1
  Rule position              : 1
  From zone                  : untrust
  Destination addresses      : Host-Public-1.1.1.10
  Host addresses             : Host-Private-10.0.100.10
  Netmask                    : 32
  Host routing-instance      : N/A
  Translation hits           : 40
    Successful sessions      : 34
    Failed sessions          : 6
  Number of sessions         : 0

Static NAT rule: NAT-DMZ-11           Rule-set: Static-From-Untrust
  Rule-Id                    : 2
  Rule position              : 2
  From zone                  : untrust
  Destination addresses      : Host-Public-1.1.1.11
  Host addresses             : Host-Private-10.0.100.11
  Netmask                    : 32
  Host routing-instance      : N/A
  Translation hits           : 112
    Successful sessions      : 112
    Failed sessions          : 0
  Number of sessions         : 0

To emphasize that no PAT is performed, here is an output of the session table. We are using port 50973 on both ends of the firewall.

Session ID: 15148, Policy name: FW-PermitWeb/7, Timeout: 4, Valid
  In: 10.0.100.11/50973 --> 91.189.92.200/80;tcp, If: ge-0/0/1.0, Pkts: 26, Bytes: 5673
  Out: 91.189.92.200/80 --> 1.1.1.11/50973;tcp, If: ge-0/0/0.0, Pkts: 25, Bytes: 5863

JNCIS-SEC – Port forwarding on the SRX

A common technique to obscure services from network probing is to host them on ports outside of the well-known ports range. This might help as a first defense, but in reality the ports are still there for anyone who steps out of the defaults. It also makes life harder for other firewall engineers 🙂 On the other hand, if your ISP is blocking services hosted in the well-known range, it might be your only option.

As in all the NAT examples, here is the topology:

SRX NAT topology

We are hosting an SFTP server, but are fed up with all the bruteforce attacks, so decide to host it on a different port. Traffic coming from the untrust zone, destined for 1.1.1.11 and arriving at TCP port 2222, will be translated to port 22 on the inside.

First, we define the real, internal port at the DNAT pool, together with the internal IP.

[edit security nat destination]
root@NP-vSRX-01# show pool DNAT-Host100-11
address 10.0.100.11/32 port 22;

Then, we go to our rule set, which defined the traffic direction (from untrust) and enter the address and port on which it should be listening, plus the pool to translate to:

[edit security nat destination rule-set DNAT-From-Untrust]
root@NP-vSRX-01# show
from zone untrust;
rule DNAT-Host100-11 {
    match {
        destination-address 1.1.1.11/32;
        destination-port {
            2222;
        }
    }
    then {
        destination-nat {
            pool {
                DNAT-Host100-11;
            }
        }
    }
}

That’s it. After doing a telnet to port 2222, we see the following flow in the table:

Session ID: 167059, Policy name: FW-SSH-Server/6, Timeout: 1778, Valid
  In: 10.6.60.68/62340 --> 1.1.1.11/2222;tcp, If: ge-0/0/0.0, Pkts: 3, Bytes: 132
  Out: 10.0.100.11/22 --> 10.6.60.68/62340;tcp, If: ge-0/0/1.0, Pkts: 2, Bytes: 126

Port forwarding with a dynamic IP

If you are running a dynamic IP address, it won’t be possible to define one IP as a match condition. Unless your ISP is always handing out addresses in one specific range, the only option is to define the destination-address as 0.0.0.0/0

All config stays the same, but the DNAT rule looks like this:

[edit security nat destination rule-set DNAT-From-Untrust rule DNAT-Host100-11]
root@NP-vSRX-01# show
match {
    destination-address 0.0.0.0/0;
    destination-port {
        2222;
    }
}
then {
    destination-nat {
        pool {
            DNAT-Host100-11;
        }
    }
}

JNCIS-SEC Lab – Destination NAT

In this lab, we will look at configuring the SRX to translate the destination field for incoming traffic, which is widely used for public servers in a DMZ.

As with all the NAT examples, I’ll be using the following topology:

SRX NAT topology

These are the requirements for the translations:

  • Only applies to traffic coming from the internet (untrust zone)
  • Destination 1.1.1.10/32 will be translated to DMZ IP 10.0.100.10/32
  • Destination 1.1.1.11/32 will be translated to DMZ IP 10.0.100.11/32

First, I will configure security policies for the following services:

  • Server 10.0.100.10 is hosting a Telnet server
  • Server 10.0.100.11 is an SSH/SFTP server

Because DNAT happens before policy lookup, we always refer to the address as it will be after translation.

[edit security policies from-zone untrust to-zone dmz]
root@NP-vSRX-01# show
policy FW-Telnet-Server {
    match {
        source-address any;
        destination-address Host-10.0.100.10-32;
        application junos-telnet;
    }
    then {
        permit;
        log {
            session-close;
        }
    }
}
policy FW-SSH-Server {
    match {
        source-address any;
        destination-address Host-10.0.100.11-32;
        application junos-ssh;
    }
    then {
        permit;
        log {
            session-close;
        }
    }
}

As this is a fresh config, we will first define a rule-set that specifies the traffic direction. Destination NAT does not give you the option to specify the to-zone, just the source zone.

[edit security nat destination]
root@NP-vSRX-01# show
rule-set DNAT-From-Untrust {
    from zone untrust;
}

Now, let’s add the two pools:

[edit security nat destination]
root@NP-vSRX-01# show
pool DNAT-Host100-11 {
    address 10.0.100.11/32;
}
pool DNAT-Host100-10 {
    address 10.0.100.10/32;
}

And here are the NAT rules themselves:

[edit security nat destination rule-set DNAT-From-Untrust]
rule DNAT-Host100-10 {
    match {
        destination-address 1.1.1.10/32;
    }
    then {
        destination-nat {
            pool {
                DNAT-Host100-10;
            }
        }
    }
}
rule DNAT-Host100-11 {
    match {
        destination-address 1.1.1.11/32;
    }
    then {
        destination-nat {
            pool {
                DNAT-Host100-11;
            }
        }
    }
}

Because the upstream router is in the same segment as our firewall, we will also need to add ProxyARP to the global NAT config.

[edit security nat]
root@NP-vSRX-01# set proxy-arp interface ge-0/0/0.0 address 1.1.1.10/32 to 1.1.1.11/32

Verification

After starting a telnet and SSH session from my PC, this is the session table:

Session ID: 166748, Policy name: FW-SSH-Server/6, Timeout: 1792, Valid
  In: 10.6.66.68/59016 --> 1.1.1.11/22;tcp, If: ge-0/0/0.0, Pkts: 3, Bytes: 132
  Out: 10.0.100.11/22 --> 10.6.66.68/59016;tcp, If: ge-0/0/1.0, Pkts: 2, Bytes: 126
Session ID: 166759, Policy name: FW-Telnet-Server/5, Timeout: 1798, Valid
  In: 10.6.66.68/60731 --> 1.1.1.10/23;tcp, If: ge-0/0/0.0, Pkts: 11, Bytes: 510
  Out: 10.0.100.10/23 --> 10.6.66.68/60731;tcp, If: ge-0/0/1.0, Pkts: 14, Bytes: 652
root@NP-vSRX-01> show security nat destination summary
Total pools: 2
Pool name            Address                           Routing        Port  Total
                     Range                             Instance             Address
DNAT-Host100-11      10.0.100.11    - 10.0.100.11                     0     1
DNAT-Host100-10      10.0.100.10    - 10.0.100.10                     0     1

Total rules: 2
Rule name            Rule set       From                               Action
DNAT-Host100-11      DNAT-From-Untrust untrust                         DNAT-Host100-11
DNAT-Host100-10      DNAT-From-Untrust untrust                         DNAT-Host100-10
root@NP-vSRX-01> show security nat destination pool all
Total destination-nat pools: 2

Pool name       : DNAT-Host100-11
Pool id         : 3
Total address   : 1
Translation hits: 1
Address range                        Port
    10.0.100.11 - 10.0.100.11           0

Pool name       : DNAT-Host100-10
Pool id         : 4
Total address   : 1
Translation hits: 8
Address range                        Port
    10.0.100.10 - 10.0.100.10           0