If your system has PMDF-X400 installed, then you may be able to use it to send mail to X.400 subscribers on other systems. However, be warned that the information provided here is very general. In practice, the required information which you must supply to properly identify an X.400 addressee varies considerably from site to site as well as between X.400 service providers. You may find that you need very specific information in order to successfully address a message to a given X.400 subscriber (e.g., what PRMD and ADMD to specify, whether or not initials are required, whether or not an organizational unit must be specified, etc.).

For sending mail to local X.400 users, you should consult your system manager or postmaster to determine the precise addressing conventions which you should use.

PMDF X.400 addresses have the format

"/attribute1=value1/attribute2=value2/.../"@X400-gateway-domain

where X400-gateway-domain is a domain name which was selected by your system manager when PMDF-X400 was installed. attribute1, attribute2, ... are any of the attribute names listed in Table 1-1 and value1, value2, ... are allowed values for the corresponding attributes. Consult your system manager for the proper domain name to use for X400-gateway-domain.

Table 1-1 X.400 Attribute Names Recognized by PMDF-X400

PMDF-X400 name	X.400 attribute
C	Country
ADMD	Administrative Domain
PRMD	Private Domain
O	Organization
OU	Organizational Unit (up to four of these fields are allowed)
S	Surname
G	Givenname
I	Initials
DD.xx	Domain Defined Attribute "xx"

Now, assuming that the X400-gateway-domain domain name is x400.example.com, then a sample X.400 address might be

"/g=John/s=Doe/o=Example Corporation/"@x400.example.com

This address specifies the recipient John Doe of the Example Corporation.

If any spaces or other special characters from the list of RFC 822 "specials" characters

( ) < > @ , ; : \ " . [ ]

appear amongst the attributes or values in the X.400 ORname portion of the address (the local-part of the address), then the entire local-part of the address must be enclosed in quotes, ". For instance, in the example above the space in Example Corporation has caused the entire local-part to require quoting.

An additional quoting is required when any of the characters =, $, or / appear in an attribute value. These characters must be quoted by prefixing each occurrence with a dollar sign, $. For instance, if "john doe a/s" is to be specified with an Organization attribute, then it must be specified as

/o=john doe a$/s

so that the / in a/s is not confused with the normal use of / as an attribute separator.

Note also that X.400 is limited in the characters that are allowed in attribute values to the characters defined as members of the "printable string" set. Characters that are used in RFC 822 (Internet) addresses but not allowed by X.400 are specified by multi-character substitutions in accordance with RFC 2156. These are particularly useful when X.400 originators need to specify a complete RFC 822 address in a DD.RFC-822 domain-defined attribute. The substitutions are listed in Table 1-2.

Table 1-2 RFC 2156 Printable String Character Substitutions ORname in Fields

Desired character	X.400 multi-character
@	(a)
%	(p)
!	(b)
"	(q)
_	(u)
(	(l)
)	(r)

For example, to specify the RFC 822 address doe@example.com using the DD.RFC-822 attribute, the "@" must be specified as "(a)":

DD.RFC-822 = doe(a)example.com