The use_cw_file feature causes the file /etc/mail/local-host-names (V8.10 and above) or /etc/sendmail.cw (V8.9 and earlier) to be read to obtain alternative names for the local host. One use for such a file might be to declare a list of hosts for which the local host is acting as the MX recipient. The use_cw_file is used like this:

FEATURE(`use_cw_file')

This feature causes the following F configuration command (Section 22.1.2) to appear in the configuration file:

Fw/etc/sendmail.cw           V8.9 and earlier
Fw/etc/mail/local-host-names V8.10 and above

The actual filename can be changed from the default by defining the confCW_FILE macro:

define(`confCW_FILE', `-o /etc/mail/local.list')

Here, we both rename the file and make its presence optional by adding the -o switch (Section 22.1.2).

If the local host is known by only a few names, an alternative is to instead include the mc macro in place of the earlier feature:

LOCAL_DOMAIN(`name1 name2')

Here, name1 and name2 are alternative names for the local host.