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diff --git a/doc/rfc/rfc1168.txt b/doc/rfc/rfc1168.txt new file mode 100644 index 0000000..695f185 --- /dev/null +++ b/doc/rfc/rfc1168.txt @@ -0,0 +1,1011 @@ + + + + + + +Network Working Group A. Westine +Request for Comments: 1168 A. DeSchon + J. Postel + C.E. Ward + USC/ISI + July 1990 + + INTERMAIL AND COMMERCIAL MAIL RELAY SERVICES + + +STATUS OF THIS MEMO + + This RFC discusses the history and evolution of the Intermail and + Commercial mail systems. The problems encountered in operating a + store-and-forward mail relay between commercial systems such as + Telemail, MCI Mail and Dialcom are also discussed. This RFC provides + information for the Internet community, and does not specify any + standard. Distribution of this memo is unlimited. + +INTRODUCTION + + The evolution of large electronic mail systems testifies to the + increasing importance of electronic mail as a means of communication + and coordination throughout the scientific research community. + + This paper is a summary of the development of, and a status report + on, an experiment in protocol interoperation between mail systems of + different design. USC/Information Sciences Institute (ISI) began work + on this experiment in 1981 and over the years has provided an + evolving demonstration service for users to exchange mail between the + Internet and a few commercial mail systems. + + Recently other organizations have begun to provide similar services, + demonstrating the ongoing need for interoperation of the Internet and + the commercial mail systems. We believe that ISI's pioneering work + in this area has promoted this expansion of service. + + These systems include the Internet mail system, the US Sprint + Telemail system, the MCI Mail system, and the Dialcom systems. All of + the systems were designed to operate autonomously, with no convenient + mechanism to allow users of one system to send electronic mail to + users on another system. + + The Intermail and Commercial Mail Relay (CMR) services described in + this paper were developed to provide a means for sending mail between + the Internet and these commercial mail systems. + + + + + +Westine, DeSchon, Postel & Ward [Page 1] + +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. + + <<< Figure 1 - Internet to Internet Mail >>> + + 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 [Page 2] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + As it became apparent that the level of generality of Source Route + Forwarding was not needed, and as Intermail gained acceptance among + users, an easier approach to addressing was developed. The new + addressing model is called "Simple Forwarding". This form of + addressing, like Source Route Forwarding, appears at the beginning of + the text of each message. It can be used to include various Internet + mail header fields in addition to the standard "To" and "Cc" address + fields. This format also allows the use of special address formats, + such as U.S. postal addresses and TELEX addresses, which are + supported by the MCI Mail system. The Intermail system performed + partially automated error handling. Error messages were created by + the Intermail program and were then either approved or corrected by a + human postmaster. + + Figure 2 illustrates the pathways between the user mailboxes in the + commercial mail systems and the user mailboxes in the Internet via + the Intermail accounts and program modules. Figure 3 shows the + Intermail processing in more detail. + + <<< Figure 2 - Commercial Mail to Intermail >>> + + <<< Figure 3 - Intermail Processing >>> + +COMMERCIAL MAIL RELAY + + In 1988, the Commercial Mail Relay (CMR) was developed to run on a + dedicated UNIX system, replacing the TOPS-20-based Intermail system. + The CMR is a store-and-forward mail link between the Internet and two + commercial systems, Telemail and Dialcom. The only remaining + forwarding performed by the TOPS-20 Intermail system is in support of + the MCI Mail system. (This is planned for conversion to the CMR.) + The CMR supports relay-style addressing in the "Internet to + commercial system" direction, as well as Simple Forwarding in both + directions. One advantage of relay-style addressing is that users + from different commercial systems can appear on Internet mailing + lists. Another advantage is that the reply features of most Internet + user applications can be used by Internet users to respond to mail + that originated on a commercial system. Unfortunately, since we do + not have access to the address-parsing software on the commercial + systems, it is not possible for users of the commercial systems to + enter addresses directly into the message header, and they must + continue to use Simple Forwarding. + + The CMR supports automated error handling, which enables the system + to provide faster turnaround on messages containing addressing + errors, and requires much less intervention from a human postmaster. + + + + + +Westine, DeSchon, Postel & Ward [Page 3] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + +DESCRIPTION OF THE CMR SYSTEM + + The Multi-channel Memo Distribution Facility (MMDF) is used as the + system mail software because of its notion of separating the mail + queue into separate channels [5]. This makes it easy to dedicate a + channel/queue combination to each commercial system. Internet mail + comes in over the standard SMTP port, and the system parses the + destination address, queuing the message in the proper outgoing + queue. A tag can be added to outgoing traffic so that replies can be + made without any special processing at the destination site. + + The CMR uses a relay mailbox on each commercial system. Commercial + users send mail to this mailbox with a Simple Forwarding Header (SFH) + at the head of their message text. Each channel, in addition to + sending outgoing mail into the commercial system, reads all messages + in the relay mailbox and places them in a spool file in the CMR host + computer. + + The processing of the spool file is performed by a single daemon. It + parses each commercial system message header to find the sender and + subject, then it searches for and processes the SFH. The SFH + contains the destination Internet addresses. Figure 4a illustrates + the path of mail from the Internet to the commercial sytems. Figure + 4b illustrates the path from the commercial systrems to the Internet. + Note: MCI Mail is not yet implemented. + + The CMR employs a simple accounting mechanism: a shell script counts + the number of times a string marker occurs in the MMDF logs. At the + end of the month, another script uses an "awk" program to total the + number of messages sent and received with each commercial system. The + Commercial Mail Relay is being developed by Craig E. Ward. Ann + Westine served as the Postmaster for both Intermail and the CMR until + March 1989. Currently, our Action Office serves as Postmaster. + Questions may be sent to "Intermail-Request@ISI.EDU". + + <<< Figure 4a - The Internet to Commercial Systems >>> + + <<< Figure 4b - Commercial Systems to the Internet >>> + +COMMERCIAL SYSTEMS SERVED + + The CMR provides mail relay service between the Internet and two + commercial electronic mail systems: the US Sprint Telemail system + and the Dialcom system. A CMR connection to MCI Mail is under + development. MCI Mail is currently served by the TOPS-20 Intermail + system. See Appendix C for recent traffic data. + + + + + +Westine, DeSchon, Postel & Ward [Page 4] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + Telemail is an international commercial service. Some of the + Telemail systems served by the CMR include MAIL/USA, NASAMAIL/USA, + and GSFC/USA. Some government agencies, such as NASA and the + Environmental Protection Agency, have dedicated Telemail systems. + Companies also exist that purchase bulk services from Telemail and + resell the service to individuals. Omnet's Sciencenet is a very + popular example of this type of service. + + Dialcom is a commercial service similar to Telemail in that it has + facilities for allowing groups to purchase tailored services, and + some government agencies (such as the National Science Foundation and + the U.S. Department of Agriculture) have special group-access plans. + The IEEE Computer Society also has a dedicated group service, called + IEEE Compmail, which is open to members of the IEEE Computer Society. + + MCI Mail is operated by MCI and is marketed to large companies as + well as individual users. + + Specific examples of the users of Intermail and the CMR are as + follows: + + 1) Scientists in Oceanography, Astronomy, Geology, and Agriculture + use Intermail and the CMR to communicate with colleagues. Many of + these scientists have accounts on "Sciencenet", which is actually + part of a Telemail system administered by Omnet. + + (2) The IEEE Computer Society's publication editors use the Dialcom + system "Compmail" to manage the papers being prepared for their + numerous publications. Many of the authors are in university + departments with access to the Internet. Intermail and the CMR + support a significant exchange of large messages containing + manuscripts. + + (3) NASA uses Telemail systems for its own work and has extensive + exchanges through its own relay service, as well as Intermail and the + CMR, for communicating with university scientists on the Internet. + + Other developments to interoperate between the Internet and + Commercial mail systems are: + + (1) The Merit gateway to Sprintmail and IEEE Compmail + + (2) The CNRI gateway to MCI Mail + + (3) The Ohio State University gateway to Compuserve, and, + + (4) NASA-Ames gateway to Telemail + + + + +Westine, DeSchon, Postel & Ward [Page 5] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + +ACCEPTABLE USE POLICY FOR INTERMAIL AND THE CMR + + The Internet is composed of many networks sponsored by many + organizations. However, all the Internet's long-haul networks are + provided by U.S. government agencies. Each of these agencies limits + the use of the facilities it provides in some way. In general, the + statement by an agency about how its facilities may be used is called + an "Acceptable Use Policy". + + The various agencies involved in the Internet are currently preparing + their Acceptable Use Policy statements. Most of these are in draft + form and have not been released as official agency statements as yet. + None of these policies are currently available as online documents. + + In the least restrictive case, all bona fide researchers and + scholars, public and private, from the United States and foreign + countries (unless denied access by national policy) are allowed + access. + + The Intermail and Commercial Mail Relay (CMR) systems at ISI are + resources provided by the Defense Advanced Research Projects Agency + (DARPA) for computing and communication. Use of these resources must + be limited to DARPA-sponsored work or other approved government + business (or must otherwise meet the acceptable use policy of DARPA), + only. + + However, DARPA, as a member of the Federal Research Internet + Coordinating Committee (FRICC), has agreed to the FRICC draft policy + for communication networks, which provides in part that: "The member + agencies of the FRICC agree to carry all traffic that meets the + Acceptable Use Policy of the originating member agency". + + Thus, e-mail messages (i.e., "traffic") that meet the Acceptable Use + Policy of an agency and pass through some facility of that agency + (i.e., "the originating member") on the way to Intermail or CMR are + allowed. + + The current member agencies of the FRICC are DARPA, NSF, DOE, NASA, + and NIH. + + BITNET and UUCP (and other) networks are interconnected to the + Internet via mail relays. It is the responsibility of the managers + of these mail relays to ensure that the e-mail messages ("traffic") + that enter the Internet via their mail relays meet the Acceptable Use + Policy of the member agency providing the Internet access. + + + + + + +Westine, DeSchon, Postel & Ward [Page 6] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + In addition, we cannot allow CMR or Intermail to be used simply as a + bridge between two commercial systems, even though CMR has this + technical capability. At least one end of the communication must be + related to FRICC acceptable use. + +DETAILS OF CMR SYSTEM USE + + The CMR host computer is Internet host INTERMAIL.ISI.EDU + (128.9.2.203). The users of the commercials system are required to + know the proper gateways between the Internet and other networks such + as BITNET, CSNET, or UUCP. Users on networks interconnected to the + Internet likewise need to know how to reach the Internet to send mail + through INTERMAIL.ISI.EDU to a commercial system. + + The relay connection to Telemail is through their host TELEMAIL/USA. + The general syntax for Telemail addresses is + "[USER/ORGANIZATION]HOST/COUNTRY", making the full address for the + relay mailbox: + + [INTERMAIL/USCISI]TELEMAIL/USA + + Users across the entire Telemail service can send mail to this + address. Users on the TELEMAIL host need only send to INTERMAIL. + + Internet users can use the basic Telemail format, append a + "%TELEMAIL" to it, and mail to the resulting address as if it really + existed on INTERMAIL.ISI.EDU, e.g.: + + [CWARD/USCISI]TELEMAIL/USA%TELEMAIL@INTERMAIL.ISI.EDU + + Note that the CMR system will accept anything before the "%TELEMAIL", + that is, the CMR does not validate Telemail addresses before + transmitting them to Telemail. + + The CMR handles Dialcom mail delivery in a similar way, but this + system has what might be called "virtual hosts". Groups can be set + up with an alias system to allow easier intra-group access. For + example, both NSF and USDA share the same Dialcom host (157); but, + while both groups send relay messages to Intermail, their actual + fully qualified Dialcom mailboxes are different. For example, NSF's + mailbox is NSF153, and USDA's mailbox is AGS9999. + + Mail going in either direction may use an embedded Simple Forwarding + Header. An SFH must be the first part of the message text. It + starts with a "Forward:" field followed by a "To:" field. "Cc:", + "Subject:", and other fields may follow the "To:" fields. The SFH is + terminated by a blank line. + + + + +Westine, DeSchon, Postel & Ward [Page 7] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + This is a template of an SFH: + + Forward: Destination-Network + To: User@host1, User@host2, + User2@host2 + Cc: User@host1 + Subject: This subject supercedes the subject in the host net header + <Blank-Line> + + Dialcom syntax is "Host-ID:User-ID", for example, 134:ABC1234. This + format will work from any Dialcom host; but users in the same group + as ABC would be able to use the user name, for example, JSMITH. + + Using the SFH format, mail to a Dialcom system could be sent as + follows: + + To: Intermail@ISI.EDU + Subject: Test Message + + Forward: Compmail + To: 134:ABC1234 + + Here is the text of the message. + + Proper destination network names include ARPA, Telemail, Compmail, + NSF-Mail, and USDA-Mail. + + It is possible for a user to make mistakes at many points in the + process. Errors are handled as automatically as possible by the CMR. + Many errors are caught in the standard Internet mail traffic, and + users receive the usual error messages from the system. Messages + with incorrect commercial system addresses or faulty SFHs are also + automatically returned to sender. Messages that the software cannot + handle are sent to the CMR's user-service mailbox, Intermail- + Request@ISI.EDU. This mailbox has been set up to take care of user + problems and to be a central distribution point for user + instructions. + +PROBLEMS + + Several problems arise from the store-and-forward nature of the CMR. + One of the biggest is that almost all of the commercial systems lack + a machine-to-machine interface -- the CMR software must mimic a human + user of the commercial system. Another problem is that the Internet + and a commercial system have different forms (or syntax) for + electronic mail addresses. A major goal of the CMR project is to + make the link between networks as transparent as possible, allowing + Internet users to use off-the-shelf mail programs. Making commercial + + + +Westine, DeSchon, Postel & Ward [Page 8] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + address formats fit the Internet standard is a major task [2]. + + Compatibility with Internet addressing standards is also a concern. + The commercial accounts are not able to take advantage of the + transparency features of the Domain Name System (DNS) (see Appendix + D); and some commercial addresses are incompatible with the Internet + syntax--this requires Internet users to continue using the older + methods. + + Another general problem to be solved is to reduce the amount of time + needed to maintain the system. Because most commercial systems force + our software to mimic a human user, automatic error detection and + handling are quite complex. The Intermail system requires human + intervention in processing failed mail. A goal of the CMR is to + fully automate these processes. + + A related problem facing the CMR, as well as its predecessor + Intermail, is the frequency with which commercial systems change + their software. The changes are usually minor and do not bother most + human users; however, the CMR depends on being able to recognize + certain strings. To avoid the necessity of rebuilding the whole CMR + when these strings change, most of the string markers are stored in + ASCII files that are read at run time. + + The translation of commercial system addresses has created a new set + of problems, most of which are caused by the use of "special" + characters by the commercial systems. + + Telemail uses square brackets ("[" and "]") around user names. While + these characters are not special by Internet standards when found in + the local part of an address, many (perhaps most) Internet mailers + refuse to accept these characters unless they are quoted. MMDF was + modified locally to correct this. + + The square bracket problem is even worse for users of IBM mainframe + machines, many of which are used on BITNET. The square bracket is + not a printable character on many BITNET IBM hosts, and all kinds of + strange addresses can result from its use. + + The colon is another example. Dialcom uses it as the delimiter + between host and mailbox. However, the colon is a special character + in the Internet mail standard [2]. Users can avoid this problem by + using the SFH and placing the Dialcom address at the beginning of the + message text. Although the CMR can accept addresses with colons, + many Internet hosts and relays are unable to accept addresses that + contain colons. Mail with colons in the address fields is often + rejected by Internet hosts and is returned to the Intermail-Request + mailbox for error processing. This can cause significant delays. + + + +Westine, DeSchon, Postel & Ward [Page 9] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + Problems have also been caused by confusion about which hosts are + mail relays between the Internet and other systems compatible with + the Internet mail standard [2]. (e.g., BITNET, UUCP, and CSNET). + When the CMR was implemented, a decision was made that the CMR would + not keep track of these mail relays. When a relay is changed, as the + BITNET mail relays were in 1988, mail may be rejected because the + host either no longer exists or refuses the mail. + + The mail relay problem is a subset of the larger problem of + communicating information about new features and changes to the user + community. Virtually none of the users of the CMR are local. Many + are hidden behind the veil of the commercial system. (Dealing with + commercial system customer support people has proven to be + frustrating -- few of them seem to understand the concept of + machine-to-machine exchanges.) Enhancements to commercial software + that necessitate minor changes can disrupt some CMR users for days. + + Another problem that has not been adequately solved is validation of + commercial system addresses and processing of failed commercial + system mail. The Telemail system will not validate a user/host + combination until after the full text of the message has been + transmitted. If a long message is sent to an invalid address, it can + be very expensive in terms of wasted time and connect charges. + + Telemail also gives inadequate information when the host is correct + but the user name is not. The failed mail notice received from + Telemail is of little use to either a human reader or the CMR + software. The only information that Telemail returns is the message + ID number -- it provides no subject, and no text to distinguish the + message from the numerous others that pass through the mailbox. + + Dialcom does a better job of validating addresses. If an address is + not recognized, the system immediately prompts for a correction. A + simple <RETURN> will delete the invalid address from the list. + + The commercial systems are geared for paying customers to send and + receive mail to other paying customers. They are not equipped to + handle reverse billing, or "collect calls." ISI is currently charged + for connect time needed to transmit and receive mail to and from + other Internet sites. A possible solution to this problem would be + to extend the CMR. to include accounting and billing procedures that + would pass the costs of CMR to its users. + + What had been GTE Telemail became Sprint SprintMail, Telenet became + Sprintnet, and the host TELEMAIL/USA became SM66/USA. + + In April 1990, Sprint installed its X.400 implementation. For the + time being, the old-style Interconnect syntax will work. The CMR + + + +Westine, DeSchon, Postel & Ward [Page 10] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + telemail channel and the Simple Forwarding Header (SFH) processor, + were modified to accept either format in the SprintMail "From" field. + + Sprint uses the following syntax for X.400: + + (O:USCISI,UN:INTERMAIL,TS:SM66) + + The SFH processor will "translate" this into: + + /O=USCISI/UN=INTERMAIL/TS=SM66/%TELEMAIL + + The channel program will reverse the process. In the translation, + parentheses become slashes, colons become equal signs and commas + become slashes and vice versa. + + Unfortunately, the translation algorithm is not foolproof. A + Sprint/Internet relay did not use the same field names and values as + those in SprintMail. Consequently, a CMR translated address can not + be sent unmodified to Sprint's relay, Sprint.COM, and Sprint.COM + processed addresses cannot be sent unmodified to the CMR. + + From experimentation, the modifications necessary to a CMR processed + address to make it acceptable to Sprint.COM are (1) take the "non- + standard" X.400 fields of "UN" and "TS" and prepend "DD." to them, + (2) add the country field and code (C:US) and (3) add the Telemail + administrative domain name (ADMD:Telemail). The above example would + become: + + /O=USCISI/DD.UN=INTERMAIL/DD.TS=SM66/ADMD=TELEMAIL/C=US/@Sprint.COM + + The country code must be changed from "US" to "USA." The CMR queue + name must also be appended: "%TELEMAIL." + + The situation is further complicated by Sprint's decision to only + relay mail to and from its own administrative domain. Other X.400 + ADMDs may be added in the future if payment problems can be overcome. + + SprintMail encoded Internet addresses are not parsed correctly by the + SFH processor, but that should not be a major problem -- who on the + Internet is going to send to the commercial side of the relay? + + When the NSF decided to terminate NSFMAIL, it became clear that the + CMR Project needed a way to get news out to the commercial users. + The CMR channel programs now are able to append a news file to the + end of messages going into the commercial networks. After + transmitting a message, each channel checks for a news file with the + channel name and if present, sends it. + + + + +Westine, DeSchon, Postel & Ward [Page 11] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + The biggest costs of the CMR are the connect times to the Sprintnet + X.25 network and the commercial machines. Making the CMR transmit + faster is the current number one problem. + + Three strategies are being pursued: + + - Improve the implementation of the current method + + - Change the method to take advantage of changes in the commercial + software + + - Upgrade the modems and increase the number of phone lines + + For a list of known problems or bugs in the CMR software, see the + Appendix of the program logic manual [6]. + +FUTURE DIRECTIONS + + No software project is ever completed, and the CMR is no exception. + There are many possible extensions, some more difficult than others. + + One addition that will be made to the CMR is a channel for + interacting with MCI Mail. MCI Mail is one of the original TOPS-20 + commercial systems that were serviced by Intermail; the CMR will need + to replace this function before all of the TOPS-20 machines are + removed from service on the Internet. + + The adaptability of the CMR is such that adding new commercial + systems should not be a major problem. Additional commercial systems + under consideration include General Electric's GENIE, Western Union's + EasyLink, and Compuserve. + + One possible addition to the CMR system could be maintenance of a + list of gateways. This would allow commercial system users to + incorporate the native address formats of other networks into the + SFHs. An advantage of this would be that users could simply tell the + CMR to forward a message to BITNET, for example, and the CMR would + find the gateway and properly format the address for that gateway. + + To increase the ease of use to Internet users, the system might treat + each commercial system as an Internet host and create DNS database + records for them. This would allow users to send mail to a non- + Internet user at an Internet-style domain name. + + Another improvement would be the possibility of accepting X.400-style + addressing. The current system rejects them. + + + + + +Westine, DeSchon, Postel & Ward [Page 12] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + In order to further reduce the hazards of string changes in the + commercial system software, an AI component could be added to the + commercial system interfaces. Such an AI component might be able to + "figure out" what marker a new prompt represents and to remember it. + +ACCESS INFORMATION + + For instructions on how to use Intermail and CMR contact Intermail- + Request@ISI.EDU. + +REFERENCES + + [1] Cohen, D., "A Suggestion for Internet Message Forwarding for + MOSIS", IEN-180, USC/Information Sciences Institute, March 1981. + + [2] Crocker, D., "Standard for the Format of ARPA Internet Text + Messages", RFC-822, University of Delaware, August 1982. + + [3] DeSchon, A. L., "MCI Mail/ARPA Mail Forwarding", USC/Information + Sciences Institute, ISI Research Report, RR-84-141, August 1984. + + [4] DeSchon, A. L., "INTERMAIL, An Experimental Mail Forwarding + System", USC/Information Sciences Institute, ISI Research + Report, RR-85-158, September 1985. + + [5] Kingston, D., "MMDF II: A Technical Review", Usenix Conference, + Salt Lake City, August 1984. + + [6] Ward, C. E., "The Commercial Mail Relay Project: Intermail on + UNIX", USC/Information Sciences Institute, 1988. + + + + + + + + + + + + + + + + + + + + + +Westine, DeSchon, Postel & Ward [Page 13] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + +APPENDIX A + + The Internet and Connected Networks + + The Internet is a network of networks interconnected by gateways or + routers. The common element is the TCP/IP protocol suite. The + Internet now includes approximately 800 networks and 100,000 host + computers. The Internet is made up of local area networks in + research institutes and university campuses, regional networks, and + long-haul networks. These resources are supported by the using + organizations and by several US goverment agencies (including DARPA, + NSF, NASA, DOE, and NIH). The long-haul networks in the Internet + are the ARPANET, the MILNET, the NSFNET Backbone, the NASA Science + Internet (NSI), and the DOE Energy Science Network (ESNET). + + Other systems using TCP/IP or other protocols may be networks of + networks or "internets" with a lower case "i". The capital "I" + Internet is the one described above. + + There are other networks with (semi-) compatible electronic mail + systems. These include BITNET (and EARN and NETNORTH), UUCP (and + EUNET), CSNET, ACSNET, and JANET. Users of electronic mail may not + necessarily be aware of the boundaries between these systems and the + Internet. + + The Domain Name System (DNS) is a mechanism used in the Internet for + translating names of host computers into addresses. The DNS also + allows host computers not directly on the Internet to have registered + names in the same style. + + BITNET (Because It's Time NETwork) + + BITNET has about 2,500 host computers, primarily at universities, in + many countries. It is managed by EDUCOM, which provides + administrative support and information services. There are three + main constituents of the network: BITNET in the United States and + Mexico, NETNORTH in Canada, and EARN in Europe. There are also + AsiaNet, in Japan, and connections in South America. Gateways exist + between BITNET and the Internet. The most common gateway used is + CUNYVM.CUNY.EDU. + + CSNET (The Computer + Science Network) + + CSNET has 180 member organizations, primarily computer science + research laboratories at universities and research institutes, + including international affiliates in more than a dozen countries. + CSNET has adopted DNS-style names for all its host computers. It is + administered by the University Corporation for Atmospheric Research + + + +Westine, DeSchon, Postel & Ward [Page 14] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + + (UCAR) and provides administrative support and information services + via the CSNET Information Center (CIC) at Bolt Beranek and Newman + (BBN). The gateway between CSNET and the Internet is RELAY.CS.NET. + + Note: CSNET and BITNET have officially merged into a single + organization as of October 1, 1989. + + UUCP (UNIX to UNIX Copy) + + UUCP is a protocol, a set of files, and a set of commands for copying + data files from one UNIX machine to another. These procedures are + widely used to implement a hop-by-hop electronic mail system. This + simple mechanism allows any UNIX host computer to join the system by + arranging a connection (dial-up or permanent) with any UNIX host + already in the system. In the basic UUCP system, mail is source + routed by the sending user through a path of connected hosts to the + destination. Currently, there are databases of connection + information (UUCP maps) and programs (pathalias) that aid in + determining routes. There is some use of DNS-style names by UUCP + hosts. EUNET is a UUCP-based network in Europe, and JUNET is a + similar net in Japan. These international branches of UUCP use DNS- + style names as well. There are many hosts that may relay mail + between UUCP and the Internet. One prominent gateway is + UUNET.UU.NET. + + JANET (Joint Academic NETwork) + + JANET is the primary academic network in the United Kingdom, linking + about 1,000 computers at about 100 universities and research + institutes. JANET has a domain name system similar to that of the + Internet, but the order of the domain name parts is opposite (with + the top-level domain on the left). The protocols used in JANET are + the UK "Coloured Books". The primary gateway between JANET and the + Internet is NSFNET-RELAY.AC.UK. + + ACSNET (Australian Computer Science Network) + + ACSNET is the principal electronic mail system for the computer + science and academic research community in Australia, connecting + about 300 sites. It works similarly to UUCP. ACSNET has a domain + naming syntax similar to that for Internet domains. The gateways + between ACSNET and the Internet are MUNNARI.OZ.AU and UUNET.UU.NET. + +APPENDIX B + + <<< Mail Systems Map >>> + + + + + +Westine, DeSchon, Postel & Ward [Page 15] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + +APPENDIX C + + March 1990 sent read total + + Telemail 1291 768 2059 + MCI Mail 56 44 100 + Compmail 634 306 940 + NSF-Mail 370 243 613 + CGnet 171 82 253 + USDA Mail 6 1 7 + BellSouth 6 10 16 + Other 0 0 0 + + Total 2534 1454 3988 + Days in Month 31 + Messages per Day 128.65 + + + April 1990 sent read total + + Telemail 1363 696 2059 + MCI Mail 40 39 79 + Compmail 771 329 1100 + CGnet 361 191 552 + USDA Mail 28 31 59 + BellSouth 98 73 17 + Other 0 0 0 + + Total 2661 1361 4022 + Days in Month 30 + Messages per Day 134.07 + + + May 1990 sent read total + + Telemail 1007 561 1568 + MCI Mail 23 12 35 + Compmail 815 359 1174 + CGnet 406 210 616 + USDA Mail 12 5 17 + BellSouth 167 93 260 + Other 0 0 0 + + Total 2430 1240 3670 + Days in Month 31 + Messages per Day 118.39 + + + + + +Westine, DeSchon, Postel & Ward [Page 16] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + +APPENDIX D + + The Domain Name System + + The Domain Name System (DNS) provides for the translation between + host names and addresses. Within the Internet, this means + translating from a name, such as "ABC.ISI.EDU", to an IP address such + as "128.9.0.123". The DNS is a set of protocols and databases. The + protocols define the syntax and semantics for a query language to ask + questions about information located by DNS-style names. The databases + are distributed and replicated. There is no dependence on a single + central server, and each part of the database is provided in at least + two servers. + + In addition to translating names to addresses for hosts that are in + the Internet, the DNS provides for registering DNS-style names for + other hosts reachable (via electronic mail) through gateways or mail + relays. The records for such name registration point to an Internet + host (one with an IP address) that acts as a mail forwarder for the + registered host. For example, the Australian host "YARRA.OZ.AU" is + registered in the DNS with a pointer to the mail relay + "UUNET.UU.NET". This gives electronic mail users a uniform mail + addressing syntax and avoids making them aware of the underlying + network boundaries. + + + + + + + + + + + + + + + + + + + + + + + + + + + +Westine, DeSchon, Postel & Ward [Page 17] + +RFC 1168 Intermail and Commercial Mail Relay Services July 1990 + + +SECURITY CONSIDERATIONS + + Security issues are not discussed in this memo. + +AUTHORS' ADDRESSES + + Ann Westine + USC/Information Sciences Instutite + 4676 Admiralty Way + Marina del Rey, CA 90292-6695 + + Phone: (213) 822-1511 + EMail: Westine@ISI.EDU + + Annette DeSchon + USC/Information Sciences Instutite + 4676 Admiralty Way + Marina del Rey, CA 90292-6695 + + Phone: (213) 822-1511 + EMail: DeSchon@ISI.EDU + + Jon Postel + USC/Information Sciences Instutite + 4676 Admiralty Way + Marina del Rey, CA 90292-6695 + + Phone: (213) 822-1511 + EMail: Postel@ISI.EDU + + Craig E. Ward + USC/Information Sciences Instutite + 4676 Admiralty Way + Marina del Rey, CA 90292-6695 + + Phone: (213) 822-1511 + EMail: Ward@ISI.EDU + + + + + + + + + + + + + + +Westine, DeSchon, Postel & Ward [Page 18] +
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