[strongSwan] Strange issue with IPv6 through ipsec

[Niccolò Belli]

Sorry for the dumb question, it isn't a bug and I found the answer using 
dcpdump:

listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
14:09:40.891358 IP6 a:b:c:301::1 > ff02::1:ff00:2: ICMP6, neighbor 
solicitation, who has a:b:c:301::2, length 32
14:09:40.891708 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, neighbor 
advertisement, tgt is a:b:c:301::2, length 32
14:09:40.891727 IP6 a:b:c:301::1 > a:b:c:301::2: ICMP6, echo request, 
seq 1, length 64
14:09:40.891778 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, echo reply, seq 
1, length 64
14:09:41.887406 IP6 a:b:c:301::1 > a:b:c:301::2: ICMP6, echo request, 
seq 2, length 64
14:09:41.887478 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, echo reply, seq 
2, length 64
14:09:42.887391 IP6 a:b:c:301::1 > a:b:c:301::2: ICMP6, echo request, 
seq 3, length 64
14:09:42.887440 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, echo reply, seq 
3, length 64
14:09:43.886647 IP6 a:b:c:301::1 > a:b:c:301::2: ICMP6, echo request, 
seq 4, length 64
14:09:43.886716 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, echo reply, seq 
4, length 64
14:09:44.886636 IP6 a:b:c:301::1 > a:b:c:301::2: ICMP6, echo request, 
seq 5, length 64
14:09:44.886687 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, echo reply, seq 
5, length 64
14:09:45.886651 IP6 a:b:c:301::1 > a:b:c:301::2: ICMP6, echo request, 
seq 6, length 64
14:09:45.886722 IP6 a:b:c:301::2 > a:b:c:301::1: ICMP6, echo reply, seq 
6, length 64
14:09:45.889830 IP6 fe80::211:d8ff:fed9:c01a > a:b:c:301::1: ICMP6, 
neighbor solicitation, who has a:b:c:301::1, length 32
14:09:45.889866 IP6 a:b:c:301::1 > fe80::211:d8ff:fed9:c01a: ICMP6, 
neighbor advertisement, tgt is a:b:c:301::1, length 24


I simply had to passthrough multicast link-local traffic.

I'm sorry but I'm really newbie to IPv6 :(

Regards,
Niccolò