[gfsd]Re: GNU TeXmacs (fwd)

[Martin Hamilton]

On Thu, Oct 25, 2001 at 01:33:49PM -0600, Richard Stallman wrote:
> We have some spam filtering now and we could add more.
> I think we should do that, rather than block off posting
> to help lists.

I think I missed the earlier messages in this thread, so this might
have been discussed already, but here goes anyway...

When we get a message which looks like sp*m, or comes from somewhere
which has sent it (not necessarily to us - cf MAPS [1]) in the past, we
can essentially freeze it for examination, bounce it back to the sender,
or discard it silently.

But which, if any, of the above to do ?

Previously when we looked at this, the consensus was that it would be a
Bad Thing to do any of the above to mail bound for the GNU lists, since
important messages (bug reports/fixes) could be lost or at least
prevented from reaching the developers of a GNU package in a timely
fashion.

We recently added rudimentary virus filtering via Nigel Metheringham's
generic Windows executable content filter for Exim. [2]

We've also, from time to time, had Exim do RBL lookups [3] and insert
an extra header into the messages it sends out if the sender's IP
address is on one of various RBL block lists.

The RBL option leaves the decision of whether to bin a particular piece
of email to the ultimate recipient, but does still mean that we pass on
potential sp*m to list subscribers.

Now that MAPS have moved to a pay-per-play option [4], we could sign up
to this.  However, there are some gotchas, e.g. if we used the BGP feed
version of RBL+, we would risk cutting off GNU hackers who happened to
be using ISPs which permitted relaying.

To pick a pathological example, see below.  This is the ISP I'm using
to login to the GNU machines from right now...  Yes, the message
did get through :-(

Cheers,

Martin


[1] http://mail-abuse.org/ (and not http://www.maps.org ;-)
[2] ftp://ftp.exim.org/pub/filter/
[3] http://www.exim.org/howto/rbl.html
[4] http://mail-abuse.org/feestructure.html


  address@hidden /martin]# telnet smtp.ntlworld.com 25
  Trying 62.253.162.40...
  Connected to smtp.ntlworld.com (62.253.162.40).
  Escape character is '^]'.
  220 mta07-svc.ntlworld.com ESMTP server (InterMail vM.4.01.03.00 201-229-121) 
ready Sun, 28 Oct 2001 22:19:42 +0000
  helo foo.bar.wibble
  250 mta07-svc.ntlworld.com
  mail from: address@hidden 
  250 Sender <address@hidden> Ok
  rcpt to: address@hidden
  250 Recipient <address@hidden> Ok
  data
  354 Ok Send data ending with <CRLF>.<CRLF>
  Subject: This isn't sp*m, but it could be...
  
  sigh :-(
  
  .
  250 Message received: address@hidden
  quit
  221 mta07-svc.ntlworld.com ESMTP server closing connection
  Connection closed by foreign host.