29.9 Rule Set 1

Rule set 1 is intended to process all sender addresses. It is rarely used but can find application at sites where all outgoing mail should appear to come from a central mail server. Rules to handle this host hiding might look like this:

R$-                 $@ $1 <@ $R>           user => user@ourdomain
R$* <@ $=w> $*      $@ $1 <@ $R> $3        user@localhost => user@ourdomain

In the LHS the $=w matches any name from a list of names by which the local host is known. In the RHS the $R contains the name of the mail server. If the mail is not from the local host, it is unchanged.

Other uses for rule set 1 might include the following:

• Normalizing senders, for example, making mail from the users operator and dumper appear to come from root .

• Hiding user login names by mapping them (through an external database) to the form firstname.lastname .

Needless to say, great care should be exercised in adding schemes such as these to your configuration file.