Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site hou3c.UUCP
Path: utzoo!watmath!clyde!burl!hou3c!Rudy.Nedved@CMU-CS-A.ARPA
From: Rudy.Nedved@CMU-CS-A.ARPA
Newsgroups: net.mail.headers
Subject: Re: smtp, errors and delivery
Message-ID: <06Mar84.014615.EN0C@CMU-CS-A>
Date: Tue, 6-Mar-84 01:46:00 EST
Article-I.D.: hou3c.373
Posted: Tue Mar  6 01:46:00 1984
Date-Received: Wed, 7-Mar-84 07:40:10 EST
References: <05Mar84.125014.DP0N@CMU-CS-A>
Sender: ka@hou3c.UUCP (Kenneth Almquist)
Lines: 35
To: don.provan@CMU-CS-A
Cc: Header-People@MIT-MC
In-Reply-To: <05Mar84.125014.DP0N@CMU-CS-A>

don,

The problem is that large number of sites including CMU's Unix machines relay
mail to another site and do not include their name in the return path. In the
example I gave the sender was something like "bazola" and it was NOT in the
mail from: line. The return path of
	"@bazola:<user>@bonzo_land"
will work in the CMU-CS-A server (independent of whether it is in the host
table) and so will
	"@[78.7.8.9]:<user>@bonzo_land"
but since my mail system knows that hosts that are in the local domain have
names that contain the character set A-Z and period it rejects the mail. The
reason behind this was I was getting some real bizarre garbage host names that
sometimes look like data or internal queueing data from the remote host. I
suspect that a large chunk of mail systems can not handle funny characters that
"happen" to be the queue file delimiter....like our Unix machines using colons
can not simply insert the return path into the queue file...some conversion has
to be done.

The other problem I have seen is that if I add the connected site name to the
return path if it is not there then when the mail is rejected, the site I did
this service for rejects the error notifcation.

I think what I will do now is change the mail server so that it adds the
connecting site host name (or address) and if an error occurs it tries to send
it back to the correct address and if that fails it replaces the address with
Postmaster@<original connecting site>.

As Doug Kingston has pointed out...we have two design philosphys in the mail
world....I didn't realize this before and I am glad I sent mail asking before
starting to shoot at sites that are different.

My apology for the length of this message.

-Rudy