OT: DNS Configuration of Outbound Email

[Matt Kettler]

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Derek Winkler wrote:

>I've got a user who's complaining that they can't send email to a particular
>domain.
>
>They're rejecting our connections because our host as announced in the ehlo
>doesn't have an A or MX record.
>
>Does this seem like a reasonable thing to require?
>
>
No, but many people do it anyway. Mostly because a lot of the viruses
out there helo with garbage strings.

>Anyone know if it is required by an RFC?
>
>
It's explicitly not required by the RFCs.

However, the RFCs do specify a host SHOULD use a resolvable FQDN in it's
HELO/EHLO whenever possible.

>I'll change my ways if it's required by an RFC though.
>
It's not required, but my suggestion would be that you should fix it
unless you have a VERY good reason not to.

That said, it does look like your DNS is failing RFC requirements on the
PTR records..

    tormail2.algorithmics.com (colo-2.algorithmics.com
[209.171.52.2]

209.171.52.2 has a ptr record of colo-2.algorithmics.com, but
colo-2.algorithmics.com has no A record.. that IS a failure to meet a
RFC requirement.

All PTR records MUST point to a hostname with a resolvable A record to
be valid (CNAMES aren't even allowed).

See  RFC 1912 section 2.1

        http://www.faqs.org/rfcs/rfc1912.html

You might also want to look at the DNSBAJAJ for your domain:
http://www.zonecut.net/dns/index.cgi

You've got some dead delegations, and some NS record mismatch in terms of primary nameserver.

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