public blacklists

[Scot L. Harris]

On Wed, 2004-12-08 at 11:25, D. D. Brierton wrote:
> On Wed, 2004-12-08 at 16:11, David Cary Hart wrote:
> 
> > >From my Postfix main.cf:
> > 
> >     reject_rbl_client dnsbl.sorbs.net,
> >     reject_rbl_client sbl-xbl.spamhaus.org,
> >     reject_rbl_client bl.spamcop.net,
> 
> I'd be curious to know if this would work in my setup. I have fetchmail
> pull mail from various POP3 mailboxes on external mailservers and
> deliver it to postfix. Now if I put the above lines in my postfix
> main.cf what would happen? fetchmail would attempt to deliver mail from
> blacklisted addresses to postfix, which would then reject it. But would
> it end up just remaining in the external POP3 box waiting to be
> downloaded by fetchmail again?
> 
> Does adding the above three lines to main.cf work with postfix without
> the addition of any other packages?

I don't think you can use those rbls with fetchmail.  The message has
already been delivered to your mailbox.  All the cases I know an rbl is
used on the receiving MTA which is your ISPs server.  I believe
fetchmail is simply accessing your pop3 account on that server and
transferring the messages to your local system.  It is not acting as an
MTA so you don't have the opportunity to reject the message.  

Now you may be able to use the rbls in some kind of filter that all your
messages get run through at which point you would just drop those
messages on the floor.   But you would still have to process each
message.  

What you could do is implement spamassassin, the new version 3.0 has
SURBL support which I have heard is very very good.  But you will still
be processing each message.

This is one of the great reasons for being able to run your own email
server.  Most ISPs will not implement the various spam tools available
since there are some people out there that like to get spam for some
reason.  If they would implement greylisting alone that would help
tremendously.

-- 
Scot L. Harris
webid at cfl.rr.com

When you speak to others for their own good it's advice;
when they speak to you for your own good it's interference.