tcp versus udp

[Sam Wilson]

In article <gtrbsa$296l$1 at sf1.isc.org>, Mark Elkins <mje at posix.co.za> 
wrote:

> One place that TCP may make sense - if you are involved in a registry
> system and the process involves actually checking the information that
> you are given, including nameservers (do they exist, do they serve that
> zone - correctly?) - it may make a lot of sense to do TCP Digs for the
> information (though that should probably be after a failed UDP dig - as
> a number of people do insist on disallowing Port 53 TCP).

If the registry is testing for compliant servers then a failed TCP query 
should flag the server as non-working, as would a failed UDP query.

Sam