Mail relay to customer server

[ispcomm]

I'm attaching here a working patch for the MX relay feature.

To use it update the database (via gui). In the "edit domain" page of the reseller you'll find a new field on the bottom called "MX Relay". That is the FQDN or IP address of the server that will receive the mail coming from outside.

I have not provided (yet) an option to enable this feature from the "add user" page.

The patch is against trunk (r1204, pre-rc5). It's not big deal, but touches several places (dbase, gui, templates, engine), so I'm explaining it here:

1. A new database update: I have provided the necessary functions to upgrade the database to version 5 from the gui (just click dbase update and you're set).
2. Change in the engine to account for the new feature from dbase
3. Change in the ispcp-functions (gui/include)
4. Change in the reseller edit domain (the new option is on the bottom).
5. New translation is necessary for the new fields (currently english only).

Inner workings:

I'm using the postfix transport table (which was currently unused) to place the mx relay server. When the "mx relay" variable is set to a value different to the default ("_no_") the domain is removed from the "domain" table and a transport entry is placed in the "transport" table.

The transport table is used for unknown things in "ispcp-mbox-mngr". My patch concentrates on the ispcp-dmn-mngr. There're no conflicts between the tables and the patch is much lighter this way (as opposted to adding an extra table and backup to ALL configurations of ALL distributions).

The functionality of aliases, pop3 accounts etc is left untouched (but not guaranteed to work when MX is used). It's better to delete all accounts and aliases before using the MX relay.

The patch has been tested on debian etch but should have no problems on other platforms as well.

feedback is welcome.

ispcomm.