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@bagder OK it looked consistent until the second to last one...

@bagder This looks like a bug in your host's stdlib. With #musl on Alpine I get an error for 018.1.1.1, as expected.

@dalias @bagder Can confirm broken behaviour under glibc 2.39 on Ubuntu 24.04 (default resolver config w/ systemd-resolved).

@dalias @astraleureka as mentioned elsewhere in this thread, it's my DNS that is "helpful"!

@bagder @astraleureka It's cursed that this is even making it to DNS...

@dalias @astraleureka it is actually a pretty weak design that an IP address with wrong syntax is instead treated as a hostname and just passed along instead of outright rejected.

@dalias @bagder nss providers are just "files dns" as per defaults, but resolv.conf points to localhost. systemd-resolved synthesised an A record (*and* an NXDOMAIN) for 018.0.0.0 for some ungodly reason, but only on the first attempt. subsequent attempts seemed to have cached the NXDOMAIN. this is wildly broken

@dalias @bagder sdmzsapnsp01:/etc/bind root$ host 018.0.0.0
018.0.0.0 has address 18.0.0.0
Host 018.0.0.0 not found: 3(NXDOMAIN)

Help, I'm nauseous.

@dalias @bagder Even more batshit:

sdmzsapnsp01:/etc/bind root$ host 019.011.012.004 019.011.012.004 has address 19.11.12.4

@astraleureka @dalias when the first number is a "bad octal", they all become decimal?

@bagder @dalias yep, what a failure mode.