Tutorial: fairly-secure anti-spam gateway using OpenBSD
This document describes how to setup a spam-blocking email gateway based on open source and freely available software. This procedure is designed for a small to medium sized company with a single domain (multiple domains are possible...just not described here). I will describe how to setup a new computer that is meant to run on your network's DMZ in between the Internet and a corporate email server like Lotus Notes or Microsoft Exchange.
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