For most purposes (and assuming per-user rather than site-wide configuration) the shortest config files are as follows:
$ cat ~/.extsmail/conf
spool_dir = "~/.extsmail/spool_dir"
$ cat ~/.extsmail/externals
group {
external mymachine {
sendmail = "/usr/bin/ssh -q -C -l user mymachine.net /usr/sbin/sendmail"
}
}
$
where
mymachine is a human-friendly name given to an external (it does not effect processing), and
user is your username on the remote machine
mymachine.net.
Starting and stopping UNIX daemons is a perrenial problem, and extsmaild is not completely immune to such problems. Although multiple instances of
extsmaild can (in theory) run side-by-side without negatively impacting each other, this is likely to lead to occasionally odd behaviour, and a general waste of resources.
extsmaild therefore uses a lock file
extsmaild.lock in the spool directory. When
extsmaild is running, this lock file will be both present and
flock'd; if the lock file is present but not
flock'd,
extsmaild assumes there is not another instance is running (this case can happen e.g. after a power failure). In general this means that simply calling
extsmaild in a start-up script will do the right thing.