[CentOS] Slow DNS lookups on CentOS6

Tue Sep 27 18:02:41 UTC 2011
Les Mikesell <lesmikesell at gmail.com>

On Tue, Sep 27, 2011 at 12:28 PM, Alfred von Campe <alfred at von-campe.com> wrote:
> On Sep 27, 2011, at 11:29, John Hodrien wrote:
>
>> 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.
>
> Good point.  Using -f doesn't show a 3+ second gap, but I still have no idea
> why it's slow (3-5 seconds) compared to CentOS5, or why using ltrace causes
> host or nslookup to crash.  Can anybody else get ltrace to work with host?

The usual reason for a delay is that you have more than one nameserver
specified in resolv.conf and the first one tried is down or
unreachable so you time out and retry.  Try "dig @namserver hostname"
with each of the nameserver addresses to see if they are working or
just slow.

-- 
  Les Mikesell
    lesmikesell at gmail.com