[Greylist-users] Backup MX and forwards

[Ken Raeburn]

Lars Clausen <lc at statsbiblioteket.dk> writes:
> 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?

Yep, afraid so.  Unless you can get another server on the outside to
act as your only MX and do Greylisting, and then forward to your ISP
to forward to your real mail server.  Or get around your ISP's
policies with something like UUCP to an outside MX server.

Maybe you can sell your ISP on Greylisting, at least on a per-customer
basis?  Show them some of the stats from other big sites that have
been reported in the archives here.

> The greater part of my spam comes through my UIUC address, which is
> forwarded, most frequently through university servers (for @cs.uiuc.edu
> and @uiuc.edu addresses) that send to a server I control, which then
> forwards to raeder.dk.  While I could greylist on my own server, the
> forwarding through university servers would make greylisting useless for
> those as well, right?

Yes.

At best, a queue of delayed spam on their servers might get their
attention and get them talking to you about why some of the mail is
delayed, at which time you could pitch Greylisting to them.  At worst,
they might get annoyed at you, and stop forwarding your mail. :-) Most
likely, I think, they just wouldn't notice, and the spam would all
come through in the end anyways.

If the server you control also gets mail from other sources, there
might be a point to Greylisting there, but even if you do it, you
might as well whitelist the UIUC servers.

Ken