Postfix & Hostname problems.

[Paul Howarth]

On Wed, 2005-01-05 at 17:10 -0800, Erik Ellestad wrote:
>  > Does this mean that most people running Exchange servers that HELO as
>  > blah.local or even OEMCOMPUTER can't send you mail?
> 
> Just tragic, isn't it?
> 
> ;-)
> 
> Actually, that issue hasn't been too much a problem for me.  Responsible 
> postmasters are usually pretty quick to fix errors like that, even in 
> the edu domains.
> 
> Bigger problem are legitimate collaborators who can't figure out how to 
> get their systems patched and/or un-blacklisted.  Those are the folks 
> who prevent me from using rbl lists.

At one time I tried refusing mail from sites that used a HELO name
without a period in it. It was remarkably effective at blocking most of
the worms doing the rounds at the time. However, I run a mailing list
for non-technical people (sports fans) and it was refusing so much
"legitimate" mail (albeit from misconfigured mail servers) that I had to
turn it off. It was just too painful trying to explain to all these
people why their mail was being rejected and what they should get their
IT staff to do to fix it.

On the other hand I do use DNSBLs. The rejection message I use for
listed hosts/domains says to contact my postmaster address for queries
about why mail is being rejected. My postmaster address is whitelisted
so the mail gets through. I'll happily whitelist any non-spam sender
that contacts me this way, as well as try to help them fix the
underlying problem. I'm quite satisfied with this approach.

Paul.
-- 
Paul Howarth <paul at city-fan.org>