Re: Can't Resolve from behind firewall

[Jason Kohles <jkohles () redhat com>]

On Fri, 2002-10-18 at 08:41, Dickon Newman wrote:
> Remember that DNS is UDP port, not a TCP port.  I'm not sure about how
> you've setup your firewall, or if it even makes the distinction between the
> two (I would hope that it would!).
This myth is the cause of most of the DNS problems I've had to fix in
the past, DNS is BOTH tcp and udp, responses that are too large for a
single udp packet may be sent by tcp.

A related (but still false) commonly held belief is that udp is used for
queries and tcp for zone transfers, this frequently happens, but only
because zone transfers are larger than queries, it isn't designed to
happen that way.

-- 
Jason Kohles                                 jkohles () redhat com
Senior Engineer                 Red Hat Professional Consulting