[30604] in North American Network Operators' Group
Re: lame delegations
daemon@ATHENA.MIT.EDU (Alex Kamantauskas)
Fri Aug 18 16:48:58 2000
Date: Fri, 18 Aug 2000 15:55:42 -0400 (EDT)
From: Alex Kamantauskas <alexk@tugger.net>
To: "Gary E. Miller" <gem@rellim.com>
Cc: Joshua Goodall <joshua@roughtrade.net>, nanog@merit.edu
In-Reply-To: <Pine.LNX.4.21.0008181228090.24973-100000@catbert.rellim.com>
Message-ID: <Pine.LNX.4.21.0008181550100.9407-100000@varese.appliedtheory.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Errors-To: owner-nanog-outgoing@merit.edu
On Fri, 18 Aug 2000, Gary E. Miller wrote:
> RFC 1912, Sec 2.1:
>
> " Make sure your PTR and A records match. For every IP address, there
> should be a matching PTR record in the in-addr.arpa domain. If a
> host is multi-homed, (more than one IP address) make sure that all IP
> addresses have a corresponding PTR record (not just the first one).
> Failure to have matching PTR and A records can cause loss of Internet
> services similar to not being registered in the DNS at all. Also,
> PTR records must point back to a valid A record, not a alias defined
> by a CNAME. It is highly recommended that you use some software
> which automates this checking, or generate your DNS data from a
> database which automatically creates consistent data."
>
> I have yet to hear a convincing argument why this RFC should be
> ignored. I have seen many problems when this is ignored.
>
This raises a question that I've had for some time. This says that a "PTR
record must point to a valid A record, not an alias defined by a CNAME".
RFC 1035, Sec. 3.3.12 says that the PTRDNAME is a "<domain-name> which
points to some location in the domain name space" and that "PTR records
cause no additional section processing". Since RFC 1035, Sec. 3.3 states
that a <domain-name> is just a label, and says nothing that the label has
to have a corresponding A record. Since RFC 1912 is informational and
does not update RFC 1035, it would seem that a PTR record does *not* have
to point to a host that resolves.
No? Am I getting lost in the fine print? Am I missing a later RFC that
clarifies this?
--
Alex Kamantauskas
alexk@tugger.net
