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Miscellaneous Unusual Types of Email Address X400

X.400 is an international electronic mail standard. The standard supports all email features which anyone could conceivably want in addition to quite a few that in practice no one would ever need. It was planned that this would be the main protocol used on JANET, but the popularity of SMTP based email and developments such as MIME have forced a strategy adjustment. The system is widely used in some organisations, and a certain amount of international traffic flows using X.400. Developments with personal computers may increase its use as time goes on, although currently it is not seen as a strategic direction which Information Services should take.
There are no X.400 services offered at Birmingham, but there is a gateway between X.400 mail and JANET Grey Book mail. This is called mhs–relay.ac.uk.

The term for an email system based on X.400 standards is MHS (message handling system). This is not to be confused with a commercial product of the same name. The corresponding ISO number for the X.400 standard is ISO 10021.

This section attempts to explain how to use mhs–relay.ac.uk and the basics of X.400 addressing. Further details can be obtained by accessing the Janet NEWS system (news.janet.ac.uk).

X.400 addresses

These are often referred to as O/R addresses (Originator Recipient), and consist of attributes and values used in addressing. Usually, not all the possible attributes are present.
Most of the common attributes are listed below

I - InitialsG - Given nameS - SurnameO - OrganisationOU - Organisational UnitPRMD - Private Management DomainADMD - Administrative Management DomainC - Country
These attributes are associated with values, and are presented either in a tabular form, or on a line, separated by semi–colons. The terms ADMD and PRMD are described later.
For example:

Initials (I) EVSurname (S) NeborOrganisation (O) Boring CompanyADMD (A) ImaginaryCountry (C) GBorI=EV;S=Nebor;O=Boring Company;ADMD=Imaginary;C=GB

The external MHS gateway

The mhs–relay.ac.uk gateway provides electronic mail connectivity between the UK Academic Community and X.400 electronic mail. MHS–RELAY provides protocol conversion in addition to its connectivity service. For X.400 users, MHS-RELAY provides transparent relaying to all its connected systems.
MHS systems are grouped together to form Management Domains (MDs); these are systems operated by a single management. The UK Academic Community operates as a single MD. There are two types of MD: ADMDs (Administration Management Domains) which collectively provide a global public message relaying service; and PRMDs (Private Management Domains) which provide services to their own user community. The UK Academic Community operates as a PRMD, and uses the name UK.AC (see later section on MHS addressing).

MHS-RELAY is connected to the four major ADMDs in the UK, and most PRMDs. This gives good worldwide connectivity. A list of MDs known to be reachable from MHS-RELAY is available from the info–server on MHS-RELAY.

MHS addressing

Almost any MHS O/R address can be reached from a normal RFC 822 Mailer by quoting it and putting it in place of the normal mail name, and sending it to mhs-relay. e.g.
"/I=EV/S=Nebor/O=Boring Company/ADMD=Imaginary/C=GB/"@mhs-relay.ac.uk

The number of attributes varies depending on the address. The sequence of attributes may generally be given in any order. However, if there are multiple organisational units, they are normally given "least significant first", as in a traditional postal address.

In order to convert between types of addresses and check them, there is a service at mhs-relay. A telnet call can be made to

orac.mhs-relay.ac.uk

A login: prompt is displayed. Login as "orac". Entering "?" will display help.

Your own O/R address

All UK Academic Community electronic mail users have an O/R address, which can be derived from their email address. This is achieved by mapping the normal email address into appropriate attributes.
For example, the address E.V.Nebor@birmingham.ac.uk can be expressed in X.400 terms as

ISO 10021/X.400:Initials (I) EVSurname (S) NeborOrganisation (0) BirminghamPRMD (P) UK.ACCountry (C) GBOr in non-tabular formI=EV; S=Nebor; O=Birmingham; P=UK.AC; A= ; C=GB
There is no ADMD. In the case of addresses on JANET, this takes the value of a single space. Some remote systems require an ADMD in the address. In these cases, any British ADMD should work.

Last Updated 30 Jan 2002. Please mail any comments to C.B.Bayliss@bham.ac.uk