On 2026-09-22 10:18:10 +0700, Max Nikulin wrote: > It seems, resolv.conf(5) was not updated by commits related to the bug > 27929. From <file:///usr/share/doc/libc6/NEWS.gz>: > > > Version 2.41 > > * The DNS stub resolver now supports the strict-error option. If > > activated, getaddrinfo for the AF_UNSPEC address family (with dual > > A/AAAA DNS lookups) attemps to obtain an A/AAAA response pair from > > another DNS server if one of the responses indicates failure. Without > > the strict-error option, getaddrinfo returns the A record data it has > > obtained even if the AAAA query failed. The new strict error mode is > > incompatible with some DNS environments which do not follow the RFCs, > > which is why this mode is not enabled by default. A future version > > of the library may turn it on by default, however. > > It doesn't look better than "no-aaaa" as a workaround.
The opposite of "Without the strict-error option, getaddrinfo returns the A record data it has obtained even if the AAAA query failed.", i.e. with A and AAAA reversed, would also be interesting. Perhaps it does, but since this is undocumented, one does not know. Even if it does, this is not better than "no-aaaa", because here, both DNS servers could return SERVFAIL. Note also that this option is not available on bookworm (libc 2.36). BTW, I can also see * In /etc/resolv.conf and the RES_OPTIONS environment variable, option flags can now be prefixed with “-” to clear previously set flags. For example, if /etc/resolv.conf contains “options no-aaaa”, a process running with the RES_OPTIONS=-no-aaaa environment variable performs AAAA DNS queries when the glibc DNS stub resolver is used. However, when nscd is running, RES_OPTIONS has no effect for the end user (as tested on a trixie machine). I'm wondering whether there is a way for the end user to skip nscd. This would make sense. -- Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / Pascaline project (LIP, ENS-Lyon)
