[[Caveat: I sent an earlier draft of this elswhere. Apologies
  if you see this twice. I'd assumed someone authoritative
  would've answered by now.]]

The root nameservers (ns.internic.net) lists the following
namseservers for the domain NetBSD.ORG:
	ns1.berkeley.edu,
	ns2.berkeley.edu,
	lagavulin.pdl.cs.cmu.edu
	uucp-gw-2.pa.dec.com
	uucp-gw-1.pa.dec.com

These nameservers still have ftp.netbsd.org and sup.netbsd.org as
CNAMEs pointing at sun-lamp.cs.berkeley.edu.

The above nameservers *also* list NS.NetBSD.ORG as the origin of the
netbsd.org domain in the SOA RR.  And NS.NetBSD.ORG is currently an
alias for sun-lamp.cs.berkeley.edu.  Using a CNAME as the origin
perhaps wasn't best.  Given that it's the origin that's moving, I'm
not sure what *would* have helped.

My best guess is, the primary (ie., hopefully updated)  zone file is on a
disk attached to the former sun-lamp.cs.berkeley.edu (which is now
shut down); the secondary nameservers for the NetBSD.ORG domain are
still  polling sun-lamp's IP address, since it's the origin for the
netbsd.org domain; and (since sun-lamp is down) the secondaries don't
have the updated zone file which points ftp.netbsd.org elsewhere.

Even though ns.netbsd.org isn't listed as a nameserver in the SOA, it
still appears to be the primary (ie., it's listed as the origin by all
the nameservers for the zone).  Without seeing the named config and
zone files, it's hard to be sure.

If the above is correct, fixing this DNS botch may take some time.

--Jonathan