The Mail Manager

Managing the domain table

The Mail Manager supplies a means of modifying the domain table. After installation, by default the domain table is disabled. Once enabled, and a domain table created, every address will be looked up in the domain table. If a successful match is found in the domain table, the address will be re-written as specified by the matching entry. Otherwise, the address will pass through unaltered.

The domain table allows domain addresses to be re-written, typically for the following purposes:

to map a short host name (string) into a fully qualified host (domain) name
to map a domain into a source route starting with a host
to obtain a transport address associated with a host

Enabling the domain table

Highlight the ``Domain Table Enabled'' entry.
Click on Modify.
The resulting screen presents a button to click to activate/deactivate the enabled state.
Click on the button to activate the enabled state.
Click on OK to return to the main screen.

Modifying the domain table file

Highlight the ``Domain Table File'' entry.
Click on Modify.
A pop-up screen asks if you wish to edit the domain table file.
Click on OK to edit the file.
No will cancel, and you will be returned to the main screen.

The ``Domain Table File'' screen has a scrollable field of table entries. Each entry maps the name under the ``Host'' column (first column) to the host name or route under the ``Route via'' column (second column). Tabs or spaces separate the columns. Therefore, an address which matches an entry's ``Host'' value will be re-written to take the route specified under the ``Route via'' column. Consider an example domain table entry with foo.footle.com under the ``Host'' column, and bar.footle.com under the ``Route via'' column. Then, in this example, mail addressed to user@foo.footle.com will be sent instead to user@bar.footle.com. The domain table is a simple key/value pairing. The key is the host name to be looked up in the domain table (the first column). The value includes all names on the rest of the line.

If the entry has an asterisk () in the leftmost column, then subdomain lookups (also often called partial domain matching) will be allowed on the name under the ``Host'' column. With subdomain lookups, an address does not have to match the entire name under the ``Host'' column - it may only match a part of, or rather a ``subdomain'' of, that name in order for the address to be routed as specified by that entry. This enables you to map all host names with a common subdomain to a specified host name or route. For example, consider an entry with domain name footle.com in the ``Host'' column, and other.com in the ``Route via'' column. If subdomain lookups are not allowed for this entry (that is, there is no asterisk in the leftmost column), then an address user@footle.com will match this entry, but user@foo.footle.com will not. If subdomain lookups were allowed in this example, then user@foo.footle.com would be re-written as <@other.com:user@foo.footle.com>. This is an example of source routing.

Note that you may also specify a source route by creating more than one gateway in the route for the ``Route via'' column. Again, consider an example entry, with foo.footle.com as the ``Host'' name, and hop1.footle.com > bar.caldera.com as the ``Route via'' value. To make this example simpler, we will not allow subdomain lookups on this entry. This entry rewrites any mail addressed foo.footle.com so that it first goes to hop1.footle.com before its final destination bar.caldera.com. So user@foo.footle.com will be rewritten as <@hop1.footle.com:user@bar.caldera.com>. For further information on the domain table, see UNRESOLVED XREF-0.

NOTE: The internet mail community maintains that source routing should be avoided unless absolutely necessary as it produces complicated mail addresses that not all parts of the Internet can deal with effectively.

Adding a domain table entry

Within ``Domain Table File'', click on Add.
This produces an ``Add Domain Table Entry'' screen.
Enter a host name to be matched in the ``Name'' field and enter a real host name in the ``Real Name'' field.
Note that it is mandatory to have an entry in the ``Name'' field and an entry in the ``Real Name'' field. The host name must not contain a space and must not have the same host name as an already existing entry.
The ``Route to host'' field is scrollable and has the following buttons:
- Add
- Delete
- Move Up
- Move Down
Select a ``Route to host'' field entry.

Adding a route to host

Click on Add.
This produces a pop-up ``Add to Route'' screen.
Enter a host name in the data entry field.
Click on OK and you return to the ``Add Domain Table Entry'' screen. The Select button takes you to the ``Select Host'' screen (described in ``Specifying the host name''). Note that an entry in the host name field is mandatory.
Once back at the ``Add Domain Table Entry'' screen, click on the subdomain lookups button to enable that option. Note that subdomain lookups are not allowed on numeric addresses as numeric IP addresses are not the same as a domain name.
Click on OK to enter the information and return to the domain table screen.
Select the Entry Save menu option to save. Select Entry Exit to return to the main screen.

Modifying the domain table entry

Click on Modify.
This produces a screen similar to the ``Add Domain Table Entry'' screen described in ``Adding a domain table entry''.
You can modify the table in two ways:
- Delete an entry in the ``Domain Table File'':
  1. Highlight the ``Domain Table File'' entry.
  2. Click on Delete.
- Change the order of entries:
  1. Highlight the ``Domain Table File'' entry
  2. Click the arrow buttons to move the highlighted entry to a new position in the table.
    Order of the entries is significant, as the first lookup which is successful will stop further lookups in the domain table.
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 22 April 2004