After being moved to asw2-b-eqiad, and only toward some hosts, puppetmaster1001's neighbor solicitation are at least not being received by the remote side.
Eg.
Sent by the command detailed bellow:
18:36:13.447135 IP6 fe80::1a66:daff:fe63:3d08 > ff02::1:ff61:38f4: ICMP6, neighbor solicitation, who has 2620:0:861:102:1618:77ff:fe61:38f4, length 32 18:36:14.448255 IP6 fe80::1a66:daff:fe63:3d08 > ff02::1:ff61:38f4: ICMP6, neighbor solicitation, who has 2620:0:861:102:1618:77ff:fe61:38f4, length 32 18:36:15.449377 IP6 fe80::1a66:daff:fe63:3d08 > ff02::1:ff61:38f4: ICMP6, neighbor solicitation, who has 2620:0:861:102:1618:77ff:fe61:38f4, length 32
(no replies, and they don't show up on tcpdump on the remote side):
But other are flowing (eg.)
18:36:16.795222 IP6 fe80::fe00:0:0:1 > fe80::1a66:daff:fe63:3d08: ICMP6, neighbor solicitation, who has fe80::1a66:daff:fe63:3d08, length 32 18:36:16.795263 IP6 fe80::1a66:daff:fe63:3d08 > fe80::fe00:0:0:1: ICMP6, neighbor advertisement, tgt is fe80::1a66:daff:fe63:3d08, length 24 18:36:21.868791 IP6 fe80::1a66:daff:fe63:3d08 > fe80::fe00:0:0:1: ICMP6, neighbor solicitation, who has fe80::fe00:0:0:1, length 32 18:36:21.870902 IP6 fe80::fe00:0:0:1 > fe80::1a66:daff:fe63:3d08: ICMP6, neighbor advertisement, tgt is fe80::fe00:0:0:1, length 24 18:36:36.716795 IP6 fe80::1a66:daff:fe63:3d08 > prometheus1004.eqiad.wmnet: ICMP6, neighbor solicitation, who has prometheus1004.eqiad.wmnet, length 32 18:36:36.716941 IP6 prometheus1004.eqiad.wmnet > fe80::1a66:daff:fe63:3d08: ICMP6, neighbor advertisement, tgt is prometheus1004.eqiad.wmnet, length 24 18:36:36.819577 IP6 fe80::1a66:daff:fe7e:eea3 > puppetmaster1001.eqiad.wmnet: ICMP6, neighbor solicitation, who has puppetmaster1001.eqiad.wmnet, length 32 18:36:36.819611 IP6 puppetmaster1001.eqiad.wmnet > fe80::1a66:daff:fe7e:eea3: ICMP6, neighbor advertisement, tgt is puppetmaster1001.eqiad.wmnet, length 24
puppetmaster1001:~$ ndisc6 2620:0:861:102:1618:77ff:fe61:38f4 eno1 Soliciting 2620:0:861:102:1618:77ff:fe61:38f4 (2620:0:861:102:1618:77ff:fe61:38f4) on eno1... Timed out. Timed out. Timed out. No response.
And then as soon as it has been moved back to its previous port:
puppetmaster1001:~$ ndisc6 2620:0:861:102:1618:77ff:fe61:38f4 eno1 Soliciting 2620:0:861:102:1618:77ff:fe61:38f4 (2620:0:861:102:1618:77ff:fe61:38f4) on eno1... Target link-layer address: 14:18:77:61:38:F4 from 2620:0:861:102:1618:77ff:fe61:38f4
My guess so far is a bug in Juniper's VC fabric.
I tried to disable/enable its new port with no success. ip6tables look correct.