PMDF System Manager's Guide

3.2.5 CRDB or crdb Database Operations

When using a PMDF database, (i.e., a database created with PMDF's CRDB or crdb utility), on OpenVMS and UNIX you must create a directory to hold the database files. (On NT, the appropriate directory is created during the PMDF installation.) On OpenVMS systems, use the command:

$ CREATE/DIR pmdf_root:[directories]/OWNER=[SYSTEM]

On UNIX systems, use the commands

# mkdir -mu=rwx,go= /pmdf/directories # chown pmdf /pmdf/directories

A separate database is needed for each pseudo domain. On OpenVMS, the database consists of a single database file whose name is derived from the pseudo domain name by replacing every period in the domain name with a dollar sign and appending .dat "; on UNIX and NT, the database consists of several files whose name is the actual pseudo domain name with the appropriate file type appended. For example, if the pseudo domain name is x.y , the corresponding database file would be pmdf_root:[directories]x$y.dat on an OpenVMS system. On a UNIX system, the database would be represented by the files /pmdf/directories/x.y.idx , /pmdf/directories/x.y.lck , and /pmdf/directories/x.y.pbl . On an NT system, the database would be represented by the files C:\pmdf\directories\x.y.idx , C:\pmdf\directories\x.y.lck , and C:\pmdf\directories\x.y.pbl .

3.2.5.1 Database Entries

When using a PMDF database for a pseudo domain, each entry in the database consists of a mailbox name in the pseudo domain and the corresponding "real" address.

For example, suppose the pseudo domain is example.com , the one mailbox within this pseudo domain is john.doe , and the real address corresponding to this mailbox is ariel@example.com . To set up this domain, start with a text file containing the line:

john.doe ariel@example.com

Then, on OpenVMS systems, assuming that the input text file is named example$com.txt , process this file with the PMDF CRDB utility as follows:

$ PMDF CRDB/DUPLICATES example$com.txt - $_ pmdf_root:[directories]example$com.dat_tmp $ RENAME pmdf_root:[directories]example$com.dat_tmp - $_ pmdf_root:[directories]example$com.dat

An intermediate, temporary database is used so as to minimize any window of time during which the database file is in an undefined state as it is being generated or regenerated. On UNIX systems, assuming that the input text file is named example.com.txt , use the commands

# pmdf crdb -duplicates example.com.txt /pmdf/directories/example.com

On NT systems, assuming that the input text file is named example.com.txt , use the commands

C:\> pmdf crdb -duplicates example.com.text \pmdf\directories\example.com

3.2.5.2 Default Entries

Special entries can be used to implement default redirections. Such entries are only used when no other entry matches the mailbox. The primary default rule has a single asterisk, * , as the mailbox:

* *@host.domain

In this case the message is redirected to host.domain using the original mailbox specification. An entry of the form

* newmailbox@host.domain

does the same thing except that newmailbox is used as the mailbox.

Two other special entries are available. The first is the special mailbox *%* , which matches any mailbox specification containing a percent sign. This is useful for matching and handling percent-routed addresses. The second special entry is *!* , which matches any mailbox containing an exclamation point. Both of these rules will be tried before the * rule is attempted.

3.2.5.3 Wildcard Entries

Other than the default entries listed above, the only other type of wildcard entries supported are ones where the subaddress is wildcarded. For example:

mailbox+* newmailbox@host.domain

No other wildcarding of entries is supported.

3.2.5.4 Subaddresses

The way that directory channel lookups handles subaddresses is as follows. First, the entire address including the subaddress is looked up. Second, the subaddress is replaced with the wildcard (asterisk) and that is looked up. And finally the subaddress is stripped altogether and just the mailbox is looked up.

For example, if you have an address such as "jones+spam", the complete list of variants looked up in a directory channel database is as follows:

jones+spam
jones+*
jones
*

3.2.5.5 Duplicate Entries

Databases created with CRDB or crdb can contain duplicate mailboxes (if the /DUPLICATES or -duplicates qualifier is used). The directory channel uses this capability to provide an informative way of handling ambiguous addresses. An error message is returned when the mailbox extracted from an address matches a set of duplicate entries. The addresses associated with the duplicates should be unambiguous entries associated with the pseudo domain. This list of possible addresses is returned as part of the error message so the recipient of the error can select an appropriate address to use in future messages.

For example, suppose that the example.com pseudo domain is set up to contain entries for first names, last names, and dotted combinations of first names and last names. There are bound to be ambiguities in such a scheme for some common names. Specifically, suppose that entries for John Smith, Jane Smith, and John Jones are implemented. The entries for the names John and Smith would then be ambiguous. Therefore, instead of listing an actual address for these entries it would be more appropriate to list the unambiguous equivalents in the directory. This leads to a set of entries that might look like this:

john.smith smithjo@vaxa.example.com john john.smith@example.com smith john.smith@example.com jane.smith smithja@vaxa.example.com jane smithja@vaxa.example.com smith jane.smith@example.com john.jones jj0u887@vaxb.example.com john john.jones@example.com jones jj0u887@vaxb.example.com

A message sent to smith@example.com would then produce an error message, but the message would recommend that either john.smith@example.com or jane.smith@example.com be used to disambiguate the address.

Note that PMDF contains no automatic facility to produce such databases; detection and resolution of ambiguities must be done by user-supplied programs.

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