On Tuesday 18 April 2006 13:44, Philip Hazel wrote:
> On Tue, 18 Apr 2006, listrcv wrote:
> > Which RFC does specify that an MTA must have a static IP and DNS entries?
>
> When the original RFCs were written *every* Internet host had a static
> IP. It was taken for granted. That was the way the Internet worked. But
> there was no DNS...
>
> The newer RFCs don't mention this either (I suspect - I haven't read
> every RFC). However, in practice, you will find it very hard to run an
> MTA reliably without a static IP and reverse DNS. That's just the way it
> is.
RFC1912 section 2.1 says you should have a reverse DNS for all your mail
servers. It is strongly urged that you have them, as many mailservers will
not accept mail from mailservers with no reverse DNS entry.
Every Internet-reachable host should have a name. The consequences
of this are becoming more and more obvious. Many services available
on the Internet will not talk to you if you aren't correctly
registered in the DNS.
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.
--
Casey Allen Shobe | cshobe@??? | 206-381-2800
SeattleServer.com, Inc. |
http://www.seattleserver.com
