OPNsense Forum

English Forums => Virtual private networks => Topic started by: DEC670airp414user on March 16, 2025, 01:03:03 PM

Title: where is the correct location to find and set the MTU for Wireguard
Post by: DEC670airp414user on March 16, 2025, 01:03:03 PM
OPNsense 24.10.2_6-amd64
FreeBSD 14.1-RELEASE-p7
OpenSSL 3.0.15


I've come to the conclusion that settings(5a) the manual here are being ignored : https://docs.opnsense.org/manual/how-tos/wireguard-client.html

I've tested this theory by checking system > routes > stats.    all my tunnels are 1420 which is I guess the OPNsense default wireguard MTU?   even when I have 1320 set under the normalization rule.

I then added a MTU setting to the Wireguard tunnel > instance > advance tab.     restarted the tunnel even rebooted the firewall.  and under routes > stats its still set to 1420.

I then found   by opening the interface of the tunnel.  and adding a number to MTU, and by not even restarting the tunnel.    the routes > stats is show THAT number I inputted.

1.   where is the correct location to change the MTU setting for Wireguard tunnels
2.  is system>routes > stats  really the correct location to show the currently active MTU setting for those instances?