Intermittent DNS Cache Issue with nscd on glibc 2.28 After /etc/resolv.conf Updates

[debianyu]

Hi Florian,

   Thank you again for your previous guidance on the nscd DNS caching issue. We have been investigating further and came across Bug 25420 in the glibc Bugzilla (https://sourceware.org/bugzilla/show_bug.cgi?id=25420). The description of this bug seems to closely match the intermittent issue we are experiencing—where nscd may continue to use old DNS servers after /etc/resolv.conf is updated. Is Bug 25420 indeed the same issue we are discussing?
We want to ensure we are targeting the correct fix for our production environment. Any additional details you can provide would be greatly appreciated.



Best regards,
Roy Yu









At 2025-12-19 18:32:54, "Florian Weimer" <fweimer@redhat.com> wrote:
>> Hi Florian,
>> Thank you for the clarification.
>> To confirm, is the specific bug you mentioned that was fixed in CentOS 8 Stream the same one tracked
>> at this Red Hat Bugzilla link:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1810142
>> Or does it refer to a different issue?
>
>It's a different issue.
>
>The sources of our (still maintained) 2.28 branch are here:
>
>  <https://gitlab.com/redhat/centos-stream/rpms/glibc/-/tree/c8s>
>
>You can search them for the commit ID I quoted earlier.
>
>Thanks,
>Florian