noel jones ubdarhmeganvbhcsorg alexey lobanov wrote possibly form question root difference relay_recipient_maps virtual_alias_maps difference seems cosmetic alexey two maps perform different functions relay_recipient_maps lists valid recipients remote host relay mail virtual_alias_maps generalpurpose envelope recipient rewriting map applies mail additionally map provides recipient validation domains listed virtual_alias_domains noel jones tue 05 aug 2008 224410 0600 local imap server remote