BIND 9.2.1 and TCP

[Mark_Andrews at isc.org]

> Hello,
> 	I have noticed that my BIND 9.2.1 servers are requesting that my DNS Cl
> ients use TCP rather than UDP to resolve hostnames, for all queries against t
> his server.
> 	My understanding is that UDP is used unless the packet is too large the
> n the server will request a TCP connection from the client.  I have seen this
>  occur for queries of a single A record.  Is this behavior a bug or is this a
>  new standard that is being implemented with the advent of BIND 9?
> Thanks,
> Zack

	Well the answers must be too big to fit in the space available in a
	UDP response.  Remember the authority section can also trigger TC.

	Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org