Wireguard iface - icmp6 replys from lo interface

Question

I use wireguard between 2 Debian11 and face a problem: traffic goes in to wireguard interface/ip address but goes out with lo as interface with the right ip address

19:23:50.287492 wig0 In IP6 fd99:1234:beef:cafe:fade::7000 > fd99:1234:beef:cafe:fade::7fff: ICMP6, echo request, id 18272, seq 5, length 64

19:23:50.287509 lo In IP6 fd99:1234:beef:cafe:fade::7fff > fd99:1234:beef:cafe:fade::7000: ICMP6, echo reply, id 18272, seq 5, length 64

Any clue on this ?

Thanks for your support

Daniel

Answer 1

problem is in the routing vue of the kernel

ip route get fd99:1234:beef:cafe:fade::7000 from fd99:1234:beef:cafe:fade::7fff                                                                               
anycast fd99:1234:beef:cafe:fade::7000 from fd99:1234:beef:cafe:fade::7fff dev lo table local proto kernel src fd99:1234:beef:cafe:fade::7fff metric 0 pref medium

After

ip route replace fd99:1234:beef:cafe:fade::7000 from fd99:1234:beef:cafe:fade::7fff dev wig0 table local

Everything is back to normal.