From: "Mark M." <markm@voicenet.com>
Date: Wed, 6 Nov 1996 19:58:47 -0800 (PST)
To: remailer-operators@c2.net
Subject: Blocking addresses by default
Message-ID: <Pine.LNX.3.95.961106234039.941A-100000@gak.voicenet.com>
MIME-Version: 1.0
Content-Type: text/plain


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With remailer abuse becoming more popular and remailers going down because of
complaints, there seems to be some interest in remailer software that will
block all email by default and will only pass along email that is explicitly
unblocked.  This way, someone won't receive harassing anonymous email unless
they ask to receive anonymous email.  This would also allow remailers to only
pass along mail that is destined for another remailer.  Looking at the source
code for the various remailers, this doesn't seem to be too difficult.

In the Freedom and Mixmaster remailer programs, there is a function which
determines whether an address is in the block list or not.  Both of these
functions use strstr() to search for the address in each line of the block
list.  In both programs, the strstr() call is within an if statement, so
changing the strstr() to !strstr() should invert the return value for the
blocking function.  I haven't tried this out yet, so there may be some problem
I overlooked.

The Ghio Type I program doesn't require any modification at all.  If my
understanding of the way the dest.block file is processed is correct, a file
such as the following should do the trick:

#dest.block file
*
!address1
!address2
...

All the addresses following the "!" are addresses that anonymous mail can be
delivered to.

Has anyone else managed to implement something similar to this?

Mark
- -- 
finger -l for PGP key
PGP encrypted mail prefered.

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