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One of the questions being asked by messaging system architects is: Can SMTP/MIME meet the messaging requirements of a large global enterprise? A “qualified” yes is the answer; assuming further extensions to MIME would be required, primarily in the areas of message management. Members of the IETF have shown great resiliency in further enhancing messaging functionality over the Internet when the need arises. IETF members could develop the missing pieces to make SMTP/MIME functionally similar to X.400.

Critical Comparison Factors

The most important comparisons between X.400 and SMTP/MIME concern functionality, security, systems management, message management, management manpower requirements, and performance.

Functionality

X.400 is more advanced in this respect, but developers are working to improve SMTP/MIME to match X.400’s functionality.

Security

Message security capabilities provided by the X.400 standards are far superior to SMTP/MIME. However, there are very few large-scale implementations that take advantage of the numerous security-related features specified within the standards.

Internet security is a major concern for many users. Although security options (such as software for trusted and privacy enhanced mail) exist, they are not widely and uniformly deployed.

Besides lacking security, SMTP/MIME lacks reliable audit trails. Spoofing, a process by which someone masquerades as another correspondent, is easily done via Internet mail. A user is also allowed to send a message through a rE-mailer service so that the original address is not attached to the message when it arrives at its final destination. It is therefore almost impossible to audit messages.

Systems Management

X.400 has greater potential in this respect. The entire area of management — including message management, component management, and complete MHS management — needs more attention. The experience of E-mail managers in large organizations demonstrates the need for many additional management tools for a large, complex messaging network.

Managing a Messaging System

Managing complex, enterprisewide messaging systems is difficult for several reasons:

  A lack of standards for message management.
  Interoperability — network managers have to deal with X.400, SMTP, proprietary LAN protocols, and legacy systems.
  The large number of components. An enterprisewide messaging system is composed of many different kinds of components, each with its own specific behavior characteristics (i.e., MTAs, UAs, directories, and gateways.)

Much work has been done on developing standards to govern the individual components associated with X.400. Although very little agreement has been reached on how to manage these various components. The network administrator must have tools and utilities available to manage day-to-day network operations. A fully deployed messaging system such as DMS with 2 million users will carry several million messages per day.

Industry Standards for E-mail Management

Significant work has started on developing industry standards specific to E-mail management. A joint International Federation Information Processing (IFIP) group examined the overall problem of messaging management. A similar IETF task force led to the development of RFC 1566 (also known as the Mail and Directory Management MIB, or MADMAN MIB), which defines a class of managed objects that can be deployed within any vendor’s messaging architecture. The MADMAN MIB, however, is oriented to the Internet and SMTP, and therefore lacks the ability to model some of the more complex features present in X.400-based systems.

Simple network management protocol (SNMP) and SNMP version 2, both of which are associated with the SMTP/MIME environment, are the leading protocols for managing network transport functions. However, SNMP does not work across non-TCP/IP transports. The management information base (MIB) is a definition of the managed object (i.e., what can be managed remotely). The MADMAN MIB is complete with approved standard definitions, but very limited in functionality (i.e., monitoring only). SNMP and the MIB definitions are only 5% of the puzzle, however.

The ITU-TSS and the International Standards Organization/International Electrotechnical Commission (ISO/IEC) are currently working on the following MHS management documents:

General:
MHS Management Model and Architecture X.460
MHS Management Information X.461
Management Functions for MHS:
Logging X.462
Security X.463
Configuration X.464
Fault Management X.465
Performance Management X.466

EMA Requirements for Messaging Management

The Electronic Messaging Association (EMA) is working on a framework that will allow management of multivendor messaging systems. The EMA’s work leverages the IFIP’s work and is aligned with the MADMAN MIB definitions. The effort is broad in scope because it also addresses the area of message tracing and standardizing a set of tasks for message management across a multivendor environment. The EMA’s Messaging Management Committee has characterized requirements for messaging management in the following four major categories:

  Operational management Deals with finding outages and fixing them as well as doing routine maintenance. Statistical analysis of traffic and components is accomplished. There is little difference between the two technologies — X.400 and SMTP/MIME — in this area.
  Configuration management Deals with managing the addition and deletion of components in the messaging system. It includes tasks such as dynamic updating of message routing tables, starting and stopping messaging system components, and discovering and depicting messaging system components across the network. Both X.400 and SMTP/MIME are lacking in this respect.
  Administration management Provides a means of managing subscribers, distribution lists, and accounting information. It includes facilities for security administration. Control throughout some portions of the Internet is loose. No person or group has authority over some functional subnetworks, such as Usenet, as a whole. Every administrator controls their own subnetwork. This is different from the X.400 assignment and demarcation of responsibilities, which are vested in management domains, with accountability for performance and control being highly defined. X.400 is superior in this area.
  Network management Is the process of keeping the underlying networking layer healthy. X.400 and SMTP/MIME are equal in this category.


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