The canonical mapping is not to be confused with local aliasing. When pattern matches a mail address, replace it by the corresponding result . This form has the highest precedence. This form useful to clean up addresses produced by legacy mail systems. It can also be used to pro- duce Firstname.
Lastname style addresses, but see below for a simpler solution.
This form is useful for replacing login names by Firstname. Every address in domain is replaced by address . This form has the lowest precedence. This section describes how the table lookups change when the table is given in the form of regular expressions. Each pattern is a regular expression that is applied to the entire address being looked up.