I’ve a main router using VyOS. This router is a Wireguard server (wg01) and is also connected to an OpenVPN server as a client (
vtun1). I can’t change anything on OpenVPN server (external resource).
scp on router to a computer on
vtun1 network, transfer speed is good (as expected). However, if I run the same
scp command on a client connected to Wireguard server, speed is more than ten times lower.
I guess (but I’m not sure), the issue is related to MTU
vtun1 has a MTU of 1500 and wg01 has a MTU of 1420. Maybe I need to enable TCP-MSS Clamping on router ?