3.9 The User Database

Locates mail drops when mail is received, and maps user names to their external form when mail is sent. The format of the database file (e.g., /etc/userdb) is:

user:maildrop     user@host
user:mailname     alias@external.domain

As a shorthand, if all users in a database should have their domain name changed when mail is sent, use:

:default:mailname       external.domain
user1:maildrop           user1@host
user2:maildrop           user2@host

You build the database using the makemap(1) program:

% makemap btree /etc/userdb < /etc/userdb

Berkeley database (btree class) support is required.