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A comment on CLI agents like Claude Code make self-hosting on a home server easier and fun. Parent comment

Re:CLI agents like Claude Code make self-hosting on a home s... by eqvinox on Tuesday January 13, 2026 @05:24AM (#46599222)
Uh, 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.)

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Re:CLI agents like Claude Code make self-hosting on a home s... by apstls on Tuesday January 13, 2026 @05:03PM (#46608916)
That's why you discard ICMP errors.
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Re:CLI agents like Claude Code make self-hosting on a home s... by eqvinox on Wednesday January 14, 2026 @12:09AM (#46612560)
If 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?)

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