clients unable to connect

[Kevin Darcy]

BKerr at syncrasystems.com wrote:

> Fellow Admins,
>
> We currently have an intranet with quite a few servers.  We are running a
> master dns server on this 192.168.1 network.  Bind is running fine and will
> do resolutions from the server.  However, any client that tries to connect
> to the server gets a timeout error.  Looking in the logs I see that it is
> listening on 192.168.1 and doing a netstat -a it shows up as listening on
> port 53.  I know bind uses tcp or udp and from the client machines I can
> telnet to the server on port 53 and it connects.  Why would these clients
> not be able to talk to the server?
> TIA

What exactly do you mean by the client trying to "connect to the server"? How
are you performing this "connection"? How are the clients' resolvers
configured? Note that (connectionless) UDP is the *preferred* protocol for
normal DNS queries, TCP is generally only used for zone transfers or as a
fallback. So your telnet test doesn't really simulate normal DNS traffic very
well.

The first thing I'd do is turn on query logging to see if the queries are
actually getting to the server at all. If not, it's probably a client
configuration problem (clients aren't sending queries, or aren't sending them
where you think they are), or a network/firewall/router-filter problem
(queries are being dropped/blocked).



- Kevin