"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..."
