Wireguard-kmod way too slow on 23.7.4

[shivansps]

Hi everyone, im just starting with OPNSense ive been using Mikrotik routerboards up to this point.

At work i used to have a Mikrotik as router that also worked as a wireguard vpn server, at my home i was already running a OPNsense box using a wireguard client connecting to the mikrotik router and i was able to transfer files at 10MB/s from the fileserver that is on the work network. Thats the max download speed at home so Wireguard server on the Mikrotik router + OPNsense wireguard client at home was fine.

I created a OPNsense VM on the Proxmox server at work that handles petty much everything, i got everything working fine and removed the mikrotik router, to create the wireguard server i copied the private and public keys from the mikrotik one to the new one on OPNsense, and added all peers, to my suprise eveything worked fine on first attempt.

But the speed is just terrible, i now able to get about 3.5MB/s and goes up and down constanly, before i had a constant 10MB/s. It is not a cpu issue or anything else, cpu usage is actually very low <20% on the entire server.

I tried to do a FTP transfer between the same two hosts outside the VPN and it is a constant 10MB/s, and if i connect the FTP over VPN it is again 3.5MB/s.

I have no idea of what is going on here, i really did not expect this to be a problem but its definately an issue on the server side. I tried to look for info, there seems to be a lot of people with issues, and changing the MTU wireguard interfaces does not seems to help.

Will have to try to set up another VM as a wireguard gateway to see what happens, but i really wanted to avoid that.

[lewald]

Tip: Change MSS for Wireguard Group.

[shivansps]

Thank you, that did work. Now im getting a solid 10 to 11MB/s transfer. Ill need to try with a better conection to see how fast it can go since the server has a 1 gigabit connection. But this is enoght.