Marc Powell wrote:
-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Barry Brimer Sent: Wednesday, June 29, 2005 9:47 AM To: centos@centos.org Subject: [CentOS] Postfix / Postini question
I have a mail server that handles several domains. One of these
domains
has decided to use Postini. For those not familiar with Postini, you set
your
MX records to use their mail servers. They filter mail, and deliver you
only
the clean virus/spam free mail. The idea is to only allow incoming mail
from
their mail servers so spammers are unable to send to your mail server
directly.
This is fairly simple to do with standard restriction classes for a
dedicated
mail server. I am not sure how to accomplish this on a shared mail server. Ideally I would like to instruct postfix to accept mail from anywhere for all domains except one domain (the one using Postini) and only allow mail destined
for
that specific domain to originate from Postini's mail servers. Any ideas
would
be greatly appreciated.
I'm not a postfix guru but I don't believe that is possible with a shared server. However, it's been my experience that if your server is not listed as an MX (and it won't), MXs exist (and they will -- Postini's) then mail will not be delivered to your machine by anyone except Postini. The only two scenarios I am aware of in which mail would get delivered to your server instead of Postini's would be if a) you were listed as a fallback MX or b) no MX's were specified then the A record for your domain would be used.
That is not quite true. Spammers will try the A records to send spam. Not that much, but they will.
Have you looked through the postfix wiki, documentation, faq, mailing list, etc? That'd be the first place I'd go since they _are_ the postfix experts ;).
-- Marc