On 2026-09-21 12:06:03 +0200, Marco Moock wrote: > Am 21.09.26 um 03:00 schrieb Vincent Lefevre: > > On 2026-09-20 09:23:48 +0200, Marco Moock wrote: > > > Am 19.09.26 um 23:40 schrieb Vincent Lefevre: > > > > In any case, I don't see why IPv6 support in the kernel matters > > > > for nscd. I don't see any reason why nscd would do an IPv6 > > > > connection; that's useless for name resolving. > > > > > > nscd is only a cache for libc, it does not do any lookups. The sources > > > defined in nsswitch.conf do the lookups. > > > > This is incorrect: when nscd is running, nsswitch.conf is not > > used at all by the program that calls getaddrinfo! There's only > > a connection to "/var/run/nscd/socket". > > It still does not do any DNS lookups, it uses the libraries in listed in > nsswitch.conf.
This is still part of the nscd process. > If they handle SERVFAIL improperly, it is not nscd's fault. I don't see how this is related to IPv6 support in the kernel. > > > > > > > When possible, use standard tools like getent instead of custom > > > > > > > programs or scripts. > > > > > > > > > > > > getent does *not* work in the same way. In particular, in the test, > > > > > > I got an exit status 2 in each case while IP addresses were > > > > > > available > > > > > > in each case (e.g. with getaddrinfo). And no error messages at all. > > > > > > That's very unhelpful. > > > > > > > > > > Can you give a test case? > > > > > > > > Already given, with results, in <[email protected]> > > > > (Sun, 13 Sep 2026 02:35:49 +0200). This is: > > > > > > > > #!/bin/sh > > > > getent ahostsv4 $1 || echo "Error: $?" > > > > getent ahostsv6 $1 || echo "Error: $?" > > > > getent ahosts $1 || echo "Error: $?" > > > > > > I tried that on my machine with google.com as argument, works fine. > > > > > > $ grep hosts /etc/nsswitch.conf > > > hosts: files dns > > > > > > nscd is enabled and working (I searched the cache with the strings > > > command). > > > > But I suspect that you tried with a DNS server that does not return > > random SERVFAIL errors. > > No, but I do not have one that behaves like that. This was important for the test. > But if that is the issue, you need to identify the library in nsswitch.conf > that doesn't handle the responses properly and report the bug there. This does not say how nscd uses nsswitch.conf (/etc/nsswitch.conf contains "hosts: files dns", so "dns" applies, but this does not say how name resolving is done). The nscd developers should document that first. -- 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)
