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SSH is TCP though and the outside world can initiate a handshake, the point being that wireguard silently discards unauthenticated traffic - there's no way they
by bjt12345 9mo ago
SSH is TCP though and the outside world can initiate a handshake, the point being that wireguard silently discards unauthenticated traffic - there's no way they can know the port is open for listening.
- eqvinox 9mo agoUh, you know you can scan UDP ports just fine, right? Hosts reply with an ICMP destination unreachable / port unreachable (3/3 in IPv4, 1/4 in IPv6) if the port is closed. Discarding packets won't send that ICMP error. It's slow to scan due to ICMP ratelimiting, but you can parallelize. (Sure, you can disable / firewall drop that ICMP error… but then you can do the same thing with TCP RSTs.)
- apstls 9mo agoThat's why you discard ICMP errors.
- eqvinox 9mo agoIf anything, that's why you discard ICMP port unreachable, which I assume you meant. If you're blanket dropping all ICMP errors, you're breaking PMTUD. There's a special place reserved in hell for that. (And if you're firewalling your ICMP, why aren't you firewalling TCP?)