On Tue, 27 Sep 2011, Alfred von Campe wrote: > Most of my desktops are still running CentOS5, but I have installed CentOS6 > on a few of them. The users on those desktops are reporting that DNS > lookups are slow, and from my brief tests, that does appear to be the case. > After some googling, I found a suggestion to disable IPv6, but that didn't > help. So I tried to figure out where the delay occurs using strace and > ltrace, but that didn't help much. When running ltrace, the process I'm > trying to trace (host, nslookup) just dies. And the output of strace does > show a 3+ second delay, but I can't figure out what it's telling me: > > The CentOS5 systems on the same network with the same /etc/resolv.conf file > do not have these delays. Has anyone else seen this or have some > suggestions as to how to debug this? You probably want to do an strace -f host blah rather than a basic strace, or I think you'll lose what's going on. Are you running either sssd or nscd on your box? I've done nothing special, and DNS seems fast enough. jh