Some sites have a number of workstations that never receive mail directly. They are usually clustered around a single mail server. Normally, all clients in a cluster like this send their mail as though the mail is from the server, and they relay all mail through that server rather than sending directly. If you have such a configuration, use a declaration such as the following:

FEATURE(`nullclient', `host.domain')

Note that the host.domain must be the fully qualified domain name of your mail server or relay to the outside world.

If you wish to prevent the nullclient version of sendmail from trying to access aliases, add this line to your mc file:

undefine(`ALIAS_FILE')

Note that this works only with V8.8 and above .mc files.