sendmail, 4th Edition

Handling UUCP Locally

Hosts sometimes deliver mail to a few UUCP connections locally and forward to other UUCP connections through a knowledgeable host. The rules that handle this situation often make use of another class:

R $* <@ $=V . UUCP>     $#uucp $@ $2 $: $1                   user@localuucp
R $* <@ $+ . UUCP>      $#esmtp $@ $Y $: $1<@ $2 . UUCP>     kick upstairs

Here, the class $=V contains a list of local UUCP connections. They are matched by the first rule, which selects the uucp delivery agent. All other UUCP addresses are passed to the knowledgeable host in $Y ($Y on page 852). The user part ($:) that is given to the knowledgeable host is the original address as it appeared to the LHS.