Nslookup Times Out on A Lookup To Well-Known Hosts

Fr34k freaknetboy at yahoo.com
Fri Sep 29 17:02:21 UTC 2006

MX and DNS setup a cox.net appears to be good enough that I do not see it as a
I would suggest looking at your resolvers and their configurations.

Perhaps too many recursive queries (?). See quota reached in your syslog?

HTH -- Chris

--- Will <westes-usc at noemail.nospam> wrote:

> I have several well-known hosts that are failing A record lookups on DNS and
> I need help debugging this.
> We have the ISC Bind 9.3.0 set up on a box with a sendmail mail server, just
> to speed up the MX lookups on that box.   I go to the nslookup command line,
> and type something like the following:
>     type=mx
>     cox.net
> and what I get back is a timeout that lasts two seconds and then no
> response.
> I start a sniffer, and record while performing the above.   There is no
> question that the name server is issuing the query, and that the remote DNS
> responds with the nameserver (NS) records for cox.net.
> At this point, the sniffer trace shows that there is a timeout on simple
> Address (A) record lookups to all nameservers for cox.net.
> I confirm that result from the command line by simple nslookup to ns.cox.net
> (for example) and this does time out.
> I jump over to a UNIX box outside our network and try the same queries, and
> they all immediately work.
> What are some possible causes for this?    Could cox.net be blacklisting
> many Internet hosts on their nameservers?
> -- 
> Will

More information about the bind-users mailing list