“Virtually all servers have an option to email reports, logs,
and alerts to the server administrator. You can use a standard
heavy-duty MTA (mail transport agent) like Postfix, Sendmail, or
Exim, but that’s overkill. A simpler, more lightweight solution is
to use a specialized relay-only MTA that has only one job: sending
messages from your servers to an external mail server. This can be
a local server on your LAN, a remote mail server way across the
Internet, or even a Gmail account. There are several advantages to
doing this: using fewer system resources, simpler configuration,
less possible conflict with other mail servers, fewer potential
security holes, and messages from multiple servers going to
convenient locations.“There are at least a dozen of these floating around; we’re
going to use sSMTP on our Ubuntu Server 8.04, because it’s very
easy to use. Another similar relay-only MTA is nullmailer, which is
also easy to use. Neither one is capable of receiving mail, so you
don’t have to worry about open ports…”