DNS resolution fails after resolv.conf update

[Florian Weimer]

On 05/04/2015 05:38 PM, Stanislav Baiduzhyi wrote:

> We are facing an issue with DNS server caching on RHEL-based distros: after 
> the update of resolv.conf java application cannot resolve the hosts any more.
> 
> Reproducer is very simple:
> 1. Clean /etc/resolv.conf or connect to vpn and use vpn-only nameserver.
> 2. Launch the minimal java app [1].
> 3. Restore the /etc/resolv.conf or disconnect from vpn (/etc/resolv.conf 
> should be updated with accessible nameserver at this moment).
> 4. Notice that name resolution continues to fail.

This is a glibc bug:

  <https://sourceware.org/bugzilla/show_bug.cgi?id=984>

(I don't agree with the decision not to fix this, but I hesitate to
touch the glibc resolver code, particularly in this area.)

nscd doesn't work reliable for this use case, a further fix is needed:

  <https://sourceware.org/bugzilla/show_bug.cgi?id=14906>

(Also see rhbz#859965, currently not public.)

Would using nscd work for you?

-- 
Florian Weimer / Red Hat Product Security