At this point, you've verified that mail will have the desired default behavior and that you'll be able to both send and received validly addressed mail. To complete the installation, it may be necessary to create the appropriate dbm tables to get the desired final results.
After creating the table(s) that are required for your site, you must process them through dbm by typing make in the directory containing the tables.
If you are UUCP-only, you do not need to create any of the tables mentioned in the README.linux file. You'll just have to touch the files so that the Makefile works.
If you're UUCP-only and you talk to sites in addition to your smart-host, you'll need to add uucpxtable entries for each (or mail to them will also go through the smart host) and run dbm against the revised uucpxtable.
First, you need to make certain that mail through your RELAY_HOST is sent to them via the RELAY_MAILER.
If you have UUCP neighbors other than your RELAY_HOST, you need to ensure that mail to them has the proper behavior. Mail addressed with UUCP-style syntax to a host you talk UUCP with should go directly to them (unless you explicitly prevent it with a domaintable entry). Assume host swim is a direct UUCP neighbor of yours. Then feeding swim!fred to sendmail should produce the following result:
If you have uucpxtable entries to force UUCP delivery to certain UUCP neighbors who send their mail with Internet style domainized headers, that also needs to be tested.