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From: fair@ucbarpa.berkeley.edu.BERKELEY.EDU (Erik E. &)
Newsgroups: net.mail.headers
Subject: Re: loop control
Message-ID: <11992@ucbvax.BERKELEY.EDU>
Date: Sun, 23-Feb-86 21:03:27 EST
Article-I.D.: ucbvax.11992
Posted: Sun Feb 23 21:03:27 1986
Date-Received: Wed, 26-Feb-86 05:49:06 EST
References: <1095@brl-smoke.ARPA>
Sender: usenet@ucbvax.BERKELEY.EDU
Organization: University of California at Berkeley
Lines: 28

There have been some misconceptions and I have a point to add:

1. sendmail does loop detection by counting Received: headers,
	WITH ITS OWN HOSTNAME IN THEM. After 30 such lines (i.e.
	thirty times through this host), the letter gets mailed
	to postmaster. It does not arbitrarily throw away letters
	that have passed through 30 hosts.

2. sendmail will add a message-id to any letter passing through it
	that does not already have one. Seeing as how mailers that send
	out mail messages without message-ids are in violation of the
	relevant standards (hello TOPS-20!), this is a good thing.

3. The recnews program running here at ucbvax (the one that I hacked up)
	does leave the message-id of mail coming from the internet
	through to the USENET strictly alone (so long as it is a legal
	message-id according to RFC822).

Now. It should be possible for items originating on the ARPANET bound
for *moderated* USENET newsgroups to have multiple gateways, as long as
the originating site adds a unique message-id to the letter, and ALL of
the gateways run my hacked up recnews with changes to inews.

I've already fed the changes back to Rick Adams, rather than distribute
them myself, and when that release of netnews is official, I will try
and coordinate a multiple gateway effort.

	Erik E. Fair    ucbvax!fair     fair@ucbarpa.berkeley.edu