Re: postfix issue...

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On Fri, 2010-03-05 at 18:12 +1030, Tim wrote:
> Craig White:
> 
> > I actually have a long set of postfix rules which determine which mail
> > gets through - far more than 'simply forward and reverse checking' and
> > I'm surprised that you would think I would do less.
> 
> Might have something to do with you saying this:
> 
> "At this stage, I simply will not accept mail from any smtp server
> whose forward & reverse DNS don't match. So if you are sending me
> e-mails from server mail.example.com you better have a reverse DNS
> address that tells me that your ip address points to mail.example.com."
> 
> If you didn't mean what you said, you should have said something
> different.  Because, quite frankly, what you *said* isn't going to work.
> 
> While I set all possible domain names (web server, mail server, MX
> records, etc.), to use my domain name instead of the hosting services,
> I cannot set the PTR for my host's mail server to point to my domain.
> And neither can thousands of other people.
----
maybe AOL, Gmail, Hotmail are meaningless to your neck of the woods but
there are millions of AOL, Gmail and Hotmail users and you aren't going
to get e-mail through unless you hae a reverse PTR. For example...

http://postmaster.aol.com/guidelines/standards.html

AOL's mail servers will reject connections from any IP address that does
not have reverse DNS (a PTR record). All e-mail servers connecting to
AOL's mail servers must have valid and meaningful (not dynamic-looking)
reverse DNS records. For example: 
      * Meaningful RDNS: mail.domain.com
      * Generic RDNS: 1.2.3.4.domain.isp.com

If you can't get e-mail through to AOL or Hotmail or Gmail or ..., you
can't get e-mail through to my mail servers. Done
----
> This, is laughable, too:
> 
> > I do this for many companies that are my clients and I get absolutely
> > no complaints (and very little spam).
> 
> They're not going to know if they've not received real mail that was
> falsely identified as spam.  Nor will you know about it if you make it
> impossible to email you about it.
----
You are suggesting it is possible that the same idiot system
administrators that don't understand that a reverse DNS PTR record is
essential on any mail server today also fails to notify the sender
within minutes that his e-mail has been refused by the recipients mail
server, my experience has been that even the most misconfigured Exchange
server does in fact let the sender know.

Umm Tim, they actually know when their e-mail is rejected. While I can
whitelist some senders and some smtp servers for spam & phishing
detection, I refuse to make concessions for people that can't get a
reverse PTR record for the smtp server... the truth is I don't have to.
They aren't getting e-mail through to many of the big mail box providers
like AOL, Hotmail, etc. so their problems are much bigger than my
servers. I thought you actually understood what it takes to run a mail
server these days... I guess not.

Craig


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