Subject: IPv6 and ahost

IPv6 and ahost

From: Gisle Vanem <giva_at_bgnett.no>
Date: 2005-11-10

Shouldn't ahost handle the following lookup:
  c:\> ahost 2001:890:600:D1::100
  2001:890:600:D1::100: Domain name not found

(w/o specifying 'ahost -t aaaa' as *nix 'host' seems to require).
Comparing to 'host' as shipped with Win-XP:
  c:\> host 2001:890:600:D1::100
  0.0.1.0.0.0.0.0.0.0.0.0.0.0.0.0.1.d.0.0.0.0.6.0.0.9.8.0.1.0.0.2.ip6.arpa
  domain name pointer ns1.v6.telekom.at.

Tracing ahost, this is what tcpdump shows:

pcgv.3813 > dns03.nextgentel.net.53: 17476+ A? 2001:890:600:D1::100.broadpark.no
dns03.nextgentel.net.53 > pcgv.3813: 17476 NXDomain* 0/0/0 (51)
pcgv.3813 > dns03.nextgentel.net.53: 17477+ A? 2001:890:600:D1::100. (38)
dns03.nextgentel.net.53 > pcgv.3813: 17477 NXDomain* 0/0/0 (38)

Without looking at the code, ahost doesn't seem to identify the address as
an IPv6 address, but a *name*. This is a trace of what 'host' does:

pcgv.3814 > dns03.nextgentel.net.53: 41+ PTR? 0.0.1.0.0.0.0.0.0.0.0.0.0.0.0.0.1.d.0.0.0.0.6.0.0.9.8.0.1.0.0.2.ip6.arpa. (90)
dns03.nextgentel.net.53 > pcgv.3814: 41 1/0/0 PTR ns1.v6.telekom.at. (121)

Seems correct, except it doesn't implement RFC-2673 and the bitstring PTR format.

--gv
Received on Thu Nov 10 19:54:52 2005