Beginning with V8.12 sendmail, the vacation program reads the sendmail program's configuration file to locate the value of the MailboxDatabase option (MailboxDatabase). It scans the configuration file looking for lines that begin with the prefix:

O MailboxDatabase=

If the MailboxDatabase option is undefined, its default value is pw, which means to look up mailbox information in the passwd(5) file form of database. The mailbox database is used to find the home directory, and user and group IDs for the user. The mailbox database is ignored if the -U command-line switch is used.

The location of the configuration file is defined at compile time with _PATH_SENDMAILCF (_PATH...). If you wish to use a different configuration file, you can do so by specifying it with this -C command-line switch:

% vacation -C /etc/mail/sendmail.cf.new -i

If the configuration file listed with -C doesn't exist or is unreadable, the entire -C directive is silently ignored. If the MailboxDatabase option is found but specifies an unknown database, the following error is logged or printed and the vacation program exits:

vacation: can't open mailbox database: Service unavailable