Postfix: The Definitive Guide

Delivery to Commands

As mentioned earlier in the chapter, you can’t use local aliases, .forward files, and mailing-list programs with virtual domains delivered by the virtual delivery agent. You’ve seen that you can easily set up aliases through the virtual_alias_maps parameter, but you cannot deliver messages to a command. In this last section, we’ll look at working around that issue by demonstrating how to deliver virtual addresses to external programs. The first example sets up delivery to an autoreply program, and the second to a mailing-list manager.

Auto-responders are scripts or programs that process incoming messages and return a reply to the sender of the message without any human intervention. The autoreply program used in this example, inforeply.pl, is listed in Example 8-1. This program is meant to handle mail for a dedicated information email address. Users or customers can send a message to the address to request special information. Note that this simple example is inadequate as a general autoreply program, such as the Unix vacation command. It does not cache addresses it has already replied to, and it does not do full checking for addresses that should not receive automatic replies (see the sidebar). You might also like to enhance the program to return different types of information, based on the subject or a keyword in the body of the request messages.

Example 8-1. Simple automatic reply program

#!/usr/bin/perl -w # # inforeply.pl - Automatic email reply. # # All ...