[vox-tech] zones and DNS

ME vox-tech@lists.lugod.org
Tue, 2 Sep 2003 22:50:33 -0700 (PDT)


ME said:
[chop]
> No. You still should have (not everyone does it) a separate zone for
> "rDNS" (reverse DNS lookups). This separate zone is often referred to as
> the "in-addr-arpa" version/file/zone. This allows remote DNS/clients to
> lookup the owner of a "class" and then consult with the class's owner what
> names are set per the IP address being reverse-looked-up.
[chop]

Consider this:
$ dig your.domain.name
(find its IP address)
(Use the IP address that it found and substitute it here for w.x.y.z)
$ dig -x w.x.y.z

In cases where the forward lookup does not match the reverse lookup, a
discrepency exists. There are mail servers that will refuse to accept mail
when the IP resolved in nslookup does not rDNS back to an equiv. name.
Such cases are often spammers, or poorly configured mail servers/DNS. (Of
course my backup MX (1 out of 3) actually accepts all mail, so I still get
mail when people don't do DNS/MX with rDNS working like they should.)

OK, so you say you don't care, and the few people that get mail from
youdon't care about rDNS. Well, I expect SpamAssassin and other spam tools
will reguard an nslookup resulting IP when rDNS-ed not equalling the
originalk domain or host, as to be "spam-like" and runs the riskffor your
e-mail to be marked as spam.

-ME