XCON: User Name Mapping Issues When Implementing MTA MIXER

ID: Q239007

The information in this article applies to:

Microsoft Exchange Server, version 5.5 SP3

SUMMARY

The MIME Internet X.400 Enhanced Relay (MIXER) (RFC 2156) does not provide any specifications for mapping variations in user names. Consequently, it is important to understand the limitations of using the address mapping scheme.

MORE INFORMATION

When the MIXER maps an SMTP address to an X.400 address, the user name mapping is as follows:

Case 1:
SMTP address is name@domain
Mapped X.400 address is s=name
Case 2:
SMTP address is firstname.lastname@domain
Mapped X.400 address is s=lastname;g=firstname
Case 3:
SMTP address is firstname.initial.lastname@domain
Mapped X.400 address is s=lastname;g=firstname;i=initial

When the MIXER maps an X.400 address to an SMTP address, the user name mapping is as follows:

Case 1:
X.400 address is s=lastname
Mapped SMTP address is lastname@domain
Case 2:
X.400 address is s=lastname;g=firstname
Mapped SMTP address is firstname.lastname@domain
Case 3:
X.400 address is s=lastname;g=firstname;i=initial
Mapped SMTP address is firstname.initial.lastname@domain

In most Exchange Server topologies, the SMTP address for users is the Exchange Server default, which is alias@domain. If the MIXER mapping strategy is in use in this environment, the SMTP-to-X.400 mapping works only if all X.400 addresses are in the following form:

X.400:c=country;a=admd;p=prmd;o=org;s=alias

This is possible only if the administrator does not populate First Name and Last Name fields during mailbox creation. The administrator can also populate the Last Name field with the alias, if necessary.

The reverse of this problem is also true if the administrator wants to provide X.400-to-SMTP mapping. If, as mentioned above, the administrator has populated the First Name and Last Name fields at mailbox creation, the X.400 address is in the following form:

X.400:c=country;a=admd;p=prmd;o=org;s=LastName;g=FirstName

The translated SMTP address in this case renders as:

FirstName.LastName@domain

This mapping does not work if the default SMTP addressing scheme of alias@domain is being used in this environment.

Additional query words: MIXER RFC2156

Keywords : exc55sp3
Version : winnt:5.5 SP3
Platform : winnt
Issue type : kbinfo