`local_recipient_maps`

This parameter specifies optional lookup tables with all users that are local with respect to `$mydestination` ("what domains to receive mail for")and `$inet_interfaces` ("network interfaces for receiving mail") . If this parameter is defined, then the SMTP server will reject mail for unknown local users.

Put tables with bare usernames such as `unix:passwd.byname` and alias maps. Example: `$alias_maps unix:passwd.byname`.

Beware: if the Postfix SMTP server runs chrooted, you may have to copy the passwd database into the jail. This is system dependent.