Autor: Walt Reed Data: A: Exim Mailing List Assumpte: Re: [Exim] localhost as SMTP server again: Dynamic IP adresses being blocked
On Wed, Jan 07, 2004 at 04:29:52PM +0530, Suresh Ramasubramanian said: > Toralf Lund [1/7/2004 4:24 PM] :
>
> >There is of course a different, perhaps more serious, problem with using
> >localhost as SMTP server setting in the MUA (see previous thread): It
> >could mean that dynamically assigned IP addresses are listed in
> >Received, and some receiver's don't like that; they block all messages
> >from addresses in dynamic ranges, at least if they belong to a major ISP.
>
> Nobody will block that unless the CONNECTING ip address (the smarthost
> you use) is a dynamic IP
The current versions of SpamAssassin tag on all IP's in the message
Received headers. Considering that dynamic IPs can be in multiple RBL
lists, you can get halfway to a block score on a dynamic alone. I've
actually opened a bug in the SA ruleset about this, but it hasn't been
addressed in months. SA should only look at the top-most Received header
and no other. While I can fix my own SA, I can't fix other's.
> If you feel paranoid about it, set up an ssh tunnel to a shell you have
> someplace with a static IP, and forward localhost:25 on the shell to
> localhost:2525 or whatever on your box.
That's one possible solution, although it's not available to most people.
The other option is to configure the relay SMTP server (again, not
available to most people) to strip (or not add) Received lines to the
header, and to add a "X-Origination-IP" or some other alternative.
It's really frustrating when anti-spam software does stupid things like
this.
