[ On Tuesday, February 19, 2002 at 11:54:15 (-0600), John Maier wrote: ]
> Subject: dig and DNS authority
>
> I know I get retrieve the list of DNS via:
> > dig -t T_NS <domainname>
> or
> > nslookup -q=NS <domainname>
> 
> How do you determine what is primary and what is secondary?
> 
> I (foolishly) loaned out my BIND book....

NS records are returned in a round-robin fashion, and you can have more
than two....

The "primary" nameserver for a zone is the one listed as the first
sub-field of the SOA record.  For example the primary server for the
zone "weird.com" is "ns.weird.com".  Not very much software cares what
the primary server is, and it doesn't even have to be listed in the NS
records (which would make it a "blind" primary).

	$ host -t soa weird.com
	weird.com           	SOA	ns.weird.com postmaster.weird.com (
				2002010722	;serial number (version)
				14400	;slave refresh period (4 hours)
				7200	;slave retry interval (2 hours)
				604800	;slave expire time (1 week)
				14400	;negative response ttl (4 hours)
				)

-- 
								Greg A. Woods

+1 416 218-0098;  <gwoods@acm.org>;  <g.a.woods@ieee.org>;  <woods@robohack.ca>
Planix, Inc. <woods@planix.com>; VE3TCP; Secrets of the Weird <woods@weird.com>