Description

This article provides steps to troubleshoot IPv6 neighborship on QFX series devices.

Symptoms

Between the 2 devices the IPv6 neighborship is not working even through the IPv6 stack is enabled on the interface.

 

Solution

When IPV6 is enabled on an interface then Neighbor Solicitation (NS) [ICMPv6 type 135 ]and Neighbor Advertisement (NA) [ICMPv6 type 136] messages are exchanged between the 2 devices.

1. We need to take the "monitor traffic interface" to confirm if the NS/NA messages are exchanged between the 2 peers.
2. The above output can be checked on both the sides to confirm if NS/NA are properly sent and received on both the devices.


>monitor traffic interface irb.20 no-resolve matching icmp6 detail


00:35:31.417553  In IP6 (class 0xc0, hlim 255, next-header: ICMPv6 (58), length: 32) 3ffe:ffff:: > 3ffe:ffff::1: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 3ffe:ffff::1
          source link-address option (1), length 8 (1): b4:8a:5f:c3:45:80
00:35:31.417636 Out IP6 (class 0xc0, hlim 255, next-header: ICMPv6 (58), length: 24) 3ffe:ffff::1 > 3ffe:ffff::: [icmp6 sum ok] ICMP6, neighbor advertisement

3. If we dont see the ICMP6 NS/NA messages in the above output accordingly we need to apply the firewall filter to confirm if those frames are received on the pfe.
For example we can apply below firewall filter for the NA messages on the L3 interface.


filter IPV6-NA {
    term 1 {
        from {
            icmp-type neighbor-advertisement;
        }
        then {
            count NA-pkt;
            log;
            accept;
        }
    }
    term 2 {
        then accept;
    }
}
}

We can check the firewall filter to see if these NA packets are received on the device pfe.

>show firewall filter IPV6-NA
>show firewall log




 

Modification History

2024-03-06 : Article Created
2024-09-09:  Modified from QFX5k to QFX with internal comments for QFX10k.