Optimize WireGuard MTU Setting To Stabilize SSH Connections

2026-03-17

After upgrading from my legacy Vodafone modem to the new Vodafone TG3442DE, my WireGuard VPN tunnel became unstable. While basic connectivity remains, I can still ping through the tunnel, interactive traffic fails. Specifically, SSH sessions hang indefinitely during login, causing my automated rsync and restic backups to fail. I searched Can NOT SSH over WireGuard on Gemini, and one of the suggestions was that, while small packets (ICMP) are passing through, the new hardware is dropping or blocking larger data packets, causing SSH to hang.…