· min read
The firewall rule that allowed WireGuard and blocked it anyway
A WireGuard tunnel to a Hetzner VPS sent 670 KiB and received nothing. The firewall had an ALLOW rule for port 51820. Both facts were true — because the rule said TCP and WireGuard is UDP. A debugging war story, and the method that found it: bisect the packet path.
#networking
#wireguard
#debugging
#opinion
#ai-assisted