[Greylist-users] Backup MX and forwards

[Ed Mills]

Lars,
	If greylisting fails for you, I'd be happy to share my experiences
with ORFEE. Blacklisting isn't perfect, but it works pretty well. If you
choose the right list you can catch most spam without significant false
positives. I put my phone number in so that the few false positives can call
me and correct the problem. If you don't run Windows servers, I think you
can run it on XP Pro and only expose port 25. (If not, it only requires the
smallest version of the server and 1 CAL. No Exchange)

Ed

-----Original Message-----
From: Lars Clausen [mailto:lc at statsbiblioteket.dk] 
Sent: Thursday, September 23, 2004 12:40 AM
To: Greylisting Users and Developers Discussion
Subject: Re: [Greylist-users] Backup MX and forwards


On Wed, 2004-09-22 at 19:32, Dave Anderson wrote:
> ** Reply to message from Lars Clausen <lc at statsbiblioteket.dk> on Wed, 
> 22 Sep 2004 16:33:57 +0200
> 
> >My current mail server raeder.dk is behind a backup MX system that my 
> >ISP requires, blocking SMTP from all other hosts.  This is common in 
> >Denmark as a measure to... decrease spam:(  This would make 
> >greylisting at my current server impossible, yes?
> 
> Since greylisting depends on having a direct connection from the 
> originating server, yes -- the enforced detour through your ISP's 
> server prevents you from using greylisting.  (But I am not an 
> 'expert', so be sure to have this confirmed by one.)

Seems to be confirmed by now.  Bummer.

> I am curious as to how routing _incoming_ SMTP connections through 
> their server is supposed to reduce spam (other than subjecting you to 
> whatever spam-filtering the ISP chooses to impose, AFAIK there's no 
> way that it can); does your ISP give any explanation, or is this yet 
> another case of "we _know_ that no mere user could possibly understand 
> this; don't bother us"?

At least TDC and Tele2, two of the major ISPs here, do that.  It's annoying
to set up and makes several useful things like real backup MXes and, I see
now, greylisting impossible. 

> [Forcing _outgoing_ SMTP connections to go through the ISP's servers 
> is a different matter, and makes sense in many cases -- though it does 
> interfere with some anti-spam measures, such as SPF.]

That, on the other hand, they don't do.

-Lars