which port for nsupdate?

[/dev/rob0]

On Mon, May 09, 2011 at 02:37:04PM +0800, Jeff Pang wrote:
> which port is used by BIND for nsupdate?
> Is tcp port 53 or 953 on localhost?

At least two wrong assumptions are in this question.

Excerpt from nsupdate(8) man page:
   "By default, nsupdate  uses UDP to send update requests to the 
    name server unless they are too large to fit in a UDP request
    in which case TCP will be used."

So, it's UDP. The other assumption is "... on localhost". Your other 
excerpt:
   "server  {servername} [port]

    Sends all dynamic update requests to the name server servername. 
    When no server statement is provided, nsupdate will send updates 
    to the master server of the correct zone. The MNAME field of
    that zone's SOA record will identify the master server for that
    zone."
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