Classifications in E-mail Routing (RFC1711)
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2019-Feb-12
Internet Society Requests For Comment (RFCs)
This paper presents a classification for e-mail routing issues. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.
Network Working Group J. Houttuin Request for Comments: 1711 RARE Category: Informational October 1994
Classifications in E-mail Routing
Status of this Memo
This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
This paper presents a classification for e-mail routing issues. It clearly defines commonly used terminology such as static routing, store-and-forward routing, source routing and others. Real life examples show which routing options are used in existing projects.
The goal is to define all terminology in one reference paper. This will also help relatively new mail system managers to understand the issues and make the right choices. The reader is expected to already have a solid understanding of general networking terminology.
In this paper, the word Message Transfer Agent (MTA) is used to describe a routing entity, which can be an X.400 MTA, a UNIX mailer, or any other piece of software performing mail routing functions. An MTA processes the so called envelope information of a message. The term User Agent (UA) is used to describe a piece of software performing user related mail functions. It processes the contents of a message’s envelope, i.e., the header fields and body parts.
Table of Contents
1. Naming, addressing and routing 2 2. Static versus dynamic 4 3. Direct versus indirect 5 3.1. Firewalls 5 3.2. Default versus rule based 6 4. Routing at user level 7 4.1. Distributed domains 7 4.2. Shared MTA 8 5. Routing control 9 6. Bulk routing 9 7. Source routing 11 8. Poor man’s routing 12 9. Routing communities 12
Houttuin [Page 1]
RFC 1711 Classifications in E-mail Routing October 1994
10. Realisations 14 10.1. Internet mail 14 10.2. UUCP 15 10.3. EARN 15 10.4. GO-MHS 15 10.5. ADMD infrastructure 15 10.6. Long Bud 16 10.7. X42D 16 11. Conclusion 16 12. Abbreviations 17 13. References 17 14. Security Considerations 19 15. Author’s Address 19
1. Naming, addressing and routing
A name uniquely identifies a network object (without loss of generality, we will assume the ’object’ is a person).
Once a person’s name is known, it can be used as a key to determine his address.
An address uniquely defines where the person is located. It can normally be divided into a domain related part (e.g., the RFC 822 domainpart or in X.400 an ADMD or OU attribute) and a local or user related part (e.g., the RFC 822 localpart or in X.400 a DDA or Surname attribute). The domain related part of an address typically consists of several components, which normally have a certain hierarchical order. These domain levels can be used for routing purposes, as we will see later.
Once a person’s address is known, it can be used as a key to determine a route to that person’s location.
We will use the following definition of an e-mail route:
e-mail route a path between two leaves in a directed Message Transfer System (MTS) graph that a message travels for one or...