On Thu, 26 Aug 2021 13:14:00 +0200 Daniel <t...@tootai.net> wrote: > Correction > > Le 25/08/2021 à 17:25, Daniel a écrit : > > Hi list, > > > > I setup wireguard on a server running Debian 11 and get it to work with > > 2 clients (Debian 11 and Ubuntu 20.04). Clients and server are on > > separate networks, one client behind a FW the other direct on Internet, > > no FW at all (VPS). > > > > With this setup and ipv4 connection to the public IP of the server, > > everything is working as expected, ipv4 as well as ipv6 are passing > > smoothly. > > > > Now I want to connect using the ipv6 address of the wg interface as both > > clients and server have ULA ipv6. > > Here is GUA to read. > > > This fail, wg show that connection is > > established but VPN is not usable. It's not a FW problem as I can ssh to > > the ipv6 address, as well as a netcat test from/to server IP -from each > > client- on an UDP port is working properly. Also, > > net.ipv6.conf.all.forwarding=1 is activated in sysctl.conf > > > > All network stuff is done in /etc/network/interfaces which call the > > config file. The ipv6 address of the server is affected _to the > > wireguard interface_ (in ipv4 it's another interface who take care of > > the public address) > > > > Server version is wireguard-tools v1.0.20210223. > > > > If someone have any hint, thanks to share ;) >
IPv6 requires the in-WG MTU to be 20 bytes less than when running over IPv4. Try reducing it accordingly. -- With respect, Roman