Hostname Lookup Delay and Timeout

[Jeremy Fisher]

--- Jim Levie <jim at entrophy-free.net> wrote:
> 10-15 minutes sounds way too long for a DNS problem,
> unless the DNS for
> the client's IP is exceptionally slow to respond.
> I'd expect a DNS time
> out to be on the order of 1-2 minutes.
> 
> You can check to see if a reverse lookup is really
> taking that long by
> getting the client's IP from your cyrus log and
> executing 'host
> client-IP' in a shell. If you find that taking 10-15
> minutes I'd suggest
> trying the same thing from some other Internet host
> to see if the
> problem is at your end or at the client's end.
> -- 
> Jim Levie <jim at entrophy-free.net>

It's a good thought, and I've tried that from the
shell. Took a few seconds to figure out that there was
no hostname available for the IP address -- not ten
minutes! So I'm not sure if Sendmail and Cyrus are
calling a separate process that is more persistent in
its attempts to get the hostname, or if they are just
that stubborn on their own (in which case, there must
be a feature to disable this somewhere).

As a temporary fix, I took the offending IP address
and added it to the /etc/hosts file (performance is
now lightning fast, of course). The more I look at
this, the more it appears that it is a general DNS
problem of some sort.

Thanks, all, for the help!


	
		
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