path MTU discovery problem
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Hello!
I have a gif interface with MTU 1452 set. When I send packages of 1452 bytes size it works out correctly:
20:12:05.543941 IP6 2001:XXX::2 > 2a02:2e0:3fe:1001:7777:772e:2:85: ICMP6, echo request, seq 1, length 1412
20:12:05.565816 IP6 2a02:2e0:3fe:1001:7777:772e:2:85 > 2001:XXX::2: ICMP6, echo reply, seq 1, length 1412But when i rais the size about 1 byte I expectedly get a "message to big" message:
20:14:46.282562 IP6 2001:XXX::2 > 2a02:2e0:3fe:1001:7777:772e:2:85: ICMP6, echo request, seq 1, length 1413
20:14:46.282917 IP6 2001:XXX::1 > 2001:XXX::2: ICMP6, packet too big, mtu 1452, length 1240The client learns the path mtu correctly and fragments the packages afterwards, but the fragments don't get past the pfsense router for some reason:
20:16:12.338663 IP6 2001:XXX::2 > 2a02:2e0:3fe:1001:7777:772e:2:85: frag (0|1400) ICMP6, echo request, seq 1, length 1400
20:16:12.338694 IP6 2001:XXX::2 > 2a02:2e0:3fe:1001:7777:772e:2:85: frag (1400|13)
20:16:12.339201 IP6 2001:XXX::1 > 2001:XXX::2: ICMP6, destination unreachable, unreachable address 2a02:2e0:3fe:1001:7777:772e:2:85, length 69pfsense now tells me destination is unreachable but why???
Does anyone have a clue what is going on here?