[CentOS] postfix tightening

Sat Apr 2 03:15:17 UTC 2005
Craig White <craigwhite at azapple.com>

On Fri, 2005-04-01 at 20:59 -0600, Mark A. Lewis wrote:
>  <snip>
> > > I have never understood the precived connection between reverse DNS 
> > > and spam. I have seen some go as far as if the reverse DNS does not 
> > > match the senders domain they will kick it.
> > ----
> > it doesn't seem to be too difficult to have the smtp server 
> > helo to be locatable in reverse dns - the thing that this 
> > blocks is people running smtp servers on dynamic ip space and 
> > forces them to use a smart host - can't see what the big deal 
> > is here since it provides accountability for the mail path.
> It's not a matter of difficult, nor does it provide any accountability.
> I can tell my mail server to helo whatever I want and make the ptr say
> whatever I want. It doesn't authenicate anything. Nor does someone
> running an SMTP server with a dynamic address prove anything about it
> being spam. The big problem that I have with it is that it completely
> ignores shared hosting. Not everyone wants someone to be able to look at
> the mail headers and know what company is hosting them, particularly a
> business. There are plenty of legitimate reasons to not have it.
not sure why it affects shared hosting - smtp server is smtp server -
share hosting is shared hosting.

What it means to me is that the ip space on which the smtp server is
controlled by someone and I should be able to trace it back through the
headers to someone that has control.
> > Now that AOL is doing this, it pretty much dictates that smtp 
> > servers comply with this restriction. I don't see the problem with it.
> So, you are saying that we should let AOL dictate standards? I see a
> HUGE problem with that.
AOL is just an example - they certainly forced my hand in some
instances. When they first started, I got a call from one of my clients
who are on a broadband connection where the provider REFUSES to provide
reverse dns. Smart host was the obvious solution. It hasn't had an
impact. More and more ISP's are blocking port 25 traffic except to their
smtp server which also forces peoples hands. Thus AOL is a just one of
many trying to cut down on spam. I can live with their rules - it's not
that big of a deal.