PMDF System Manager's Guide
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41.10.2 Example Domains Mapping

While originally developed for use in an Internet-wide RFC 822/X.400 gateway environment, the RFC 2156 mapping tables are more commonly used to simplify addressing problems between X.400 and RFC 822 users within an enterprise or across a few interconnected organizations.

This example assumes that the fictitious, Example Corporation is using PMDF-X400 to interconnect their X.400 user base with their non X.400 users. They have two organizations on the X.400 side, assigned X.400 addresses of the form: 


/O=Administration/PRMD=EXAMPLE/ADMD=XYZ/C=US 
/O=Bean Counters/PRMD=EXAMPLE/ADMD=XYZ/C=US

The non X.400 side of the house is using Internet domain names underneath of EXAMPLE.COM, such as: 


po1.ccmail.example.com 
vax.rnd.example.com 
unix1.engineering.example.com
Before applying RFC 2156 mapping with the x400_domains.com procedure (OpenVMS) or x400_domains.tcl TCL script (UNIX), these addresses look rather daunting to the X.400 users: 


/DD.RFC-822=user(a)po1.ccmail.example.com/O=Gateway/PRMD=EXAMPLE/ADMD=XYZ/C=US
while the non-X.400 users have to put up with things like: 


/G=First/S=Last/O=Administration/PRMD=EXAMPLE/ADMD=XYZ/C=US/@X400.EXAMPLE.COM
To make this a little easier to use, it's decided to equate some domain names with X.400 ORnames and vice versa. In particular, these pairings will be created: 


/O=ccMAIL/PRMD=EXAMPLE/ADMD=XYZ/C=US         ccmail.example.com 
/O=R and D/PRMD=EXAMPLE/ADMD=XYZ/C=US        rnd.example.com 
/O=Engineering/PRMD=EXAMPLE/ADMD=XYZ/C=US    engineering.example.com 
/O=Administration/PRMD=EXAMPLE/ADMD=XYZ/C=US admin.example.com 
/O=Bean Counters/PRMD=EXAMPLE/ADMD=XYZ/C=US  beans.example.com

Note that the first three are already existing domains on the RFC 822 side, for which new ORnames are invented, while the latter two are existing ORnames for which new domains are specified.

The mapping files, table1.map and table2.map to accomplish the address translations look like this: 6 


# 
# TABLE 1 
# ORname -> domains mappings for EXAMPLE.COM 
# 
O$R and D.PRMD$EXAMPLE.ADMD$XYZ.C$US#rnd.example.com# 
O$Administration.PRMD$EXAMPLE.ADMD$XYZ.C$US#admin.example.com# 
O$Bean Counters.PRMD$EXAMPLE.ADMD$XYZ.C$US#beans.example.com# 
PRMD$EXAMPLE.ADMD$XYZ.C$US#example.com# 



# 
# TABLE 2 
# domains -> ORname mappings for EXAMPLE.COM 
# 
rnd.example.com#O$R and D.PRMD$EXAMPLE.ADMD$XYZ.C$US# 
admin.example.com#O$Administration.PRMD$EXAMPLE.ADMD$XYZ.C$US# 
beans.example.com#O$Bean Counters.PRMD$EXAMPLE.ADMD$XYZ.C$US# 
example.com#PRMD$EXAMPLE.ADMD$XYZ.C$US#

Note that we've taken a slight shortcut here. CCMAIL.EXAMPLE.COM and ENGINEERING.EXAMPLE.COM can be handled by a single more general rule, the last one in each table, because sub-domains will, by default, be placed into separate, decreasing ORname attributes. This also handily takes care of any other domains, to a depth of up to five more levels, under EXAMPLE.COM by placing the subdomain names into O, OU1, OU2, OU3, and OU4 attribute fields to whatever depth is necessary.

Conversion of TABLE 1 and TABLE 2 into PMDF rewrite rules and PMDF-X400 address conversion databases is achieved on OpenVMS by executing the procedure x400_domains_driver.com shown in Example 41-3, or on UNIX by executing the Tcl script x400_domains_driver.tcl shown in Example 41-3. When the procedure is done, the x400.rules configuration file containing rewrite rules for PMDF-X400 needs to be augmented by adding a reference to the new x400_domains.rules file. Edit the x400.rules file in the PMDF table directory and add, for instance at the bottom of the file, the following line on OpenVMS: 


<PMDF_TABLE:x400_domains.rules
or on UNIX add the line: 


</pmdf/table/x400_domains.rules
Note that no blank lines are allowed in the x400.rules file. If a compiled PMDF configuration is in use, recompile and reinstall the configuration so that the new rules will be seen.

Once in place, these rules now allow the X.400 user to, for example, reach the cc:Mail users with addresses like: 


/S=user/OU=po1/O=ccMail/PRMD=EXAMPLE/ADMD=XYZ/C=US
Similarly, users used to RFC 822 addresses no longer need to worry about X.400 ORnames. The can use much simpler addresses such as: 


Givenname.Surname@admin.example.com

Note

6 The format of these tables is defined in RFC 2156, a copy of which is distributed with PMDF, as described in Section 41.10. In particular, note that you can not simply omit fields from the TABLE1 and TABLE2 mappings; in order to indicate an "omitted" field, you must use the special @ character as the value. For instance, a site that wanted its X.400 addresses not to use an O (Organization) field at all in favor of simply using OU (Organizational Unit) fields, and that wanted to map those various OU groups under the domain .x400.example.com, might use something like: 


# TABLE 1: 
        ORname -> domains mapping for EXAMPLE.COM 
        O$@.PRMD$EXAMPLE.ADMD$XYZ.C$US#x400.example.com#

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