Red Hat Bugzilla – Bug 77692
nameserver out of sync with redhat-config-network when caching NIS
Last modified: 2007-04-18 12:48:22 EDT
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Description of problem:
The nameserver used by the system can get out of sync with the list of DNS
servers specified by a redhat-config-network profile. This appears to happen
when "caching" is enabled by authconfig-gtk.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Logged into a network using NIS and ypbind, "caching" enabled via authconfig-gtk.
2. Shut down laptop.
3. Moved laptop to a new network without NIS, powered up.
4. ypbind failed to attach to a server as expected and timed out
5. Logged in using NIS cached authentication
6. Switched to a new network profile using redhat-config-network-cmd that
automatically used new DNS servers
Actual Results: nslookup can see new DNS server as expected. mozilla, ftp, and
other programs try to use old DNS server (on unreachable network), and don't
Expected Results: All programs should use new DNS settings.
I noticed that authconfig-gtk had added "nis" to the "hosts" line before the
"dns" entry when I enabled caching. I think that this may be the cause of the
problem, because disabling caching from authconfig-gtk made the problem go away.
re-enabling caching hasn't caused a problem, but I haven't yet returned to the
network that I use NIS on (it's at work). I'll post if I can reproduce the problem.
Enabling caching from an authentication configuration program shouldn't have the
effect of also caching the DNS server to use (at least, that's what appeared to
be happening). One final thought - maybe this is really a glibc/nscd issue, and
enabling nis lookup of hosts shouldn't affect which nameserver(s) are used. I
don't know enough about what that pair of packages does to say.
If you're using nscd, you obviously have to restart nscd if you change DNS
or nsswitch settings.
Maybe redhat-config-network should do this for you...
Yeah, I hadn't restarted nscd. That fixes it - thanks!
hmm, one should restart all network services, after switching profiles...