RFC 1168 (rfc1168) - Page 2 of 18
Intermail and Commercial Mail Relay services
Alternative Format: Original Text Document
RFC 1168 Intermail and Commercial Mail Relay Services July 1990
The Internet is an interconnected system of networks using the SMTP
mail protocol, which includes the ARPANET, MILNET, NSFNET, and about
700 other networks; mail relays allow the exchange of mail with
BITNET, CSNET, and the UUCP networks as well. To the users, this
Internet looks like one large mail system with at least 100,000
computers and at least 400,000 users. Figure 1 illustrates the path
of a message sent by a user on one Internet host to a user on another
Internet host. For more details on the Internet and connected
networks (see Appendix A).
As commercial mail systems came into popular use, it became clear
that a mail link between the Internet and the commercial mail systems
was necessary (see Appendix B). More and more commercial and
research entities needed to communicate with the Internet research
community, and many of these organizations (for one reason or
another) were inappropriate candidates for Internet sites. The
Intermail and CMR services allow these groups to communicate with
Internet users by purchasing electronic mail services from commercial
companies.
INTERMAIL
Intermail is an experimental mail forwarding system that allows users
to send electronic mail across mail system boundaries. The use of
Intermail is nearly transparent, in that users on each system are
able to use their usual mail programs to prepare, send, and receive
messages. No modifications to any of the mail programs on any of the
systems are required. However, users must put some extra addressing
information at the beginning of the body of their messages.
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The earliest version of Intermail was developed in 1981, by Jon
Postel, Danny Cohen, Lee Richardson, and Joel Goldberg [1]. It ran on
the TOPS-20 operating system and was used to forward VLSI chip
specifications for the MOSIS project between the ARPANET and the
Telemail system. The original addressing model used in this system
was called "Source Route Forwarding". It was developed to handle
situations in which a message might travel multiple hops before
reaching its destination.
Later, in 1983, Annette DeSchon converted Intermail into a more
general-purpose mail-forwarding system, supporting forwarding between
the Internet mail system and three commercial mail systems: Telemail,
MCI Mail, and Dialcom [3,4].
Westine, DeSchon, Postel & Ward