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:
As a shorthand, if all users in a database should have their domain name changed when mail is sent, use:
You build the database using the makemap(1) program:
% makemap btree
Berkeley database (btree class) support is required.