Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!cbatt!ucbvax!BIONET-20.ARPA!ROODE
From: ROODE@BIONET-20.ARPA.UUCP
Newsgroups: comp.mail.headers
Subject: MX-existence and mail header etiquette]
Message-ID: <12302764690.14.ROODE@BIONET-20.ARPA>
Date: Sat, 16-May-87 03:44:52 EDT
Article-I.D.: BIONET-2.12302764690.14.ROODE
Posted: Sat May 16 03:44:52 1987
Date-Received: Sun, 17-May-87 00:48:22 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 28

Someone said this is the end of the world where this
issue deserves the most play.  Mail sent out from non-Internet
hosts to the Internet is unrepliable in many cases because
of this problem.
                ---------------

Date: Tue 12 May 87 14:39:00-PDT
From: David Roode <ROODE@BIONET-20.ARPA>
Subject: MX-existence and mail header etiquette
To: namedroppers@SRI-NIC.ARPA
Phone: (415) 962-7322
Message-ID: <12301867965.47.ROODE@BIONET-20.ARPA>

Phase-in timetables for defacto standards are generally informal.
What's the feeling about the use of host names that are only valid
where there is support for both a host name resolver and MX name
server domain entries?  It seems reasonable for forwarding hosts to
show up in the From: header as a courtesy to those hosts who do not
yet support MX-existence.  Is this support a "required" or an
"optional" part of name resolvers?  At least considering that on some
of the networks composing the internet name server use is optional,
some period of visibilty for forwarding makes sense.

Apparently RELAY.CS.NET does follow this principle, but
not all the hosts relaying UUCP hosts' mail to the Internet
do.
-------
-------