When configuring with the
mc configuration technique, you can include
support for UUCP by using the MAILER(uucp) command
(Section 18.104.22.168) in your mc file.
With that support, you can override the use of $k
($k) with a hostname of your choosing when
prefixing a string of hosts with the local hostname:
insert local hostname here
If $U has a value, its value will be inserted. If
it lacks a value, $k will be inserted.
$U can be useful when several hosts provide UUCP
services. It can be defined in your DOMAIN( ) file (Section 22.214.171.124) as a single name so that all outgoing UUCP
mail will appear as though it is from a common host.