From: Dan Marner <dmarner@mis.nu.edu>
Date: Sat, 21 Jan 95 19:40:23 PST
To: ghio@myriad.pc.cc.cmu.edu (Matthew Ghio)
Subject: Re: jpunix.com and MX'ing
In-Reply-To: <m0rVsjT-000vEKC@myriad.pc.cc.cmu.edu>
Message-ID: <199501220337.DAA26921@mis.nu.edu>
MIME-Version: 1.0
Content-Type: text/plain



On Sat, 21 Jan 95 22:12 EST  Matthew Ghio wrote:

>
>Well, to obscure the origin of your outgoing mail, you could simply
>forward via another remailer.  However, delivering directly to SMTP
>port 25 would probably be a good idea.  Sendmail has an option to
>set the from using -f, but you have to have it configured to allow
>it.  Normally only root, uucp and daemon are allowed to use this
>option.

This still won't quite do it. Clever mailers on the other end of
the connection (sendmail included) will do a name lookup based on
the IP address.  This will (usually) return the systems canonical
name, and sendmail will make sure to stick that in the header. In 
fact, if identd is running on the sending system, it will even stick
in the userid of the sender. 

The fix involves changing the in-addr.arpa domain tables for that ip
address to make it report another name.  This will take complicity on
the part of whoever manages those tables, and will complicate things
when dealing with hosts on the remailers local network. A good way to
work around this would be to slap another ethernet card in the machine
so it has two addresses, one configured normally for that network and
the other setup to be on remailer.net (or whatever.)

Since this includes the cooperation of a local network administrator
anyway, it makes most of the MX tricks a little less useful.
                                                    -- Dan
--
Dan Marner                             dmarner@mis.nu.edu
Network Weasel                         Finger for PGP 2.6 key including the
National University                    words "GMAAAEEAK", "god" and "JAAUR"