Subj : List of IPv6 nodes To : Alexey Vissarionov From : Victor Sudakov Date : Sun Jan 09 2022 14:03:50 Dear Alexey, 09 Jan 22 09:21, you wrote to me: TK>>>>> I have a wireguard server running in my VPS (Ubuntu 20.04.3 TK>>>>> LTS). It is using a /112 of /64 for it's clients. VS>>>> Do you mean to say you can have a /64 network on your VPS' main VS>>>> interface and at the same time a /112 from the *same* *network* VS>>>> on a wg0 interface? Is this even permitted by the OS? AV>>> Yes - at least properly configured Linux allows this. VS>> What do you mean by "properly configured"? You mean the VS>> out-of-the-box configuration still does not allow this? AV> Obviously. What do you need to configure to enable this behaviour on Linux? VS>> A Cisco router would not allow the same L2 network on two VS>> different L3 interfaces IMHO, even if one of the prefixes is more VS>> specific. AV> That's a limitation of BSD-style IP stack. Interestingly enough, FreeBSD 12.3 has just let me do exactly that (sorry, an IPv4 example), without any additional configuration. The world is full of wonders: root@vas:~ # apply ifconfig lo{2,3} lo2: flags=8049 metric 0 mtu 16384 options=680003 inet 192.168.13.1/24 groups: lo nd6 options=29 lo3: flags=8049 metric 0 mtu 16384 options=680003 inet 192.168.13.129/25 groups: lo nd6 options=29 root@vas:~ # root@vas:~ # apply 'route get ' 192.168.13.2 192.168.13.200 route to: 192.168.13.2 destination: 192.168.13.0 mask: 255.255.255.0 fib: 0 interface: lo2 flags: recvpipe sendpipe ssthresh rtt,msec mtu weight expire 0 0 0 0 16384 1 0 route to: 192.168.13.200 destination: 192.168.13.128 mask: 255.255.255.128 fib: 0 interface: lo3 flags: recvpipe sendpipe ssthresh rtt,msec mtu weight expire 0 0 0 0 16384 1 0 root@vas:~ # Victor Sudakov, VAS4-RIPE, VAS47-RIPN --- GoldED+/BSD 1.1.5-b20170303-b20170303 * Origin: Ulthar (2:5005/49) .