Introduction

Electronic mail is a vital service for any company and having a healthy one – free of spam, viruses and other malware – is sometimes very hard to achieve. SMTP sits at the core of communication between MTAs (Mail Transfer Agents – otherwise known as “email servers”) and it is the main way through which unwanted emails enter the company. Scanning email traffic over SMTP will definitely improve the quality of the email service.

POP3 protocol is widely used to retrieve email from servers where the user has one or more email accounts. If the email retrieved from the server is already filled with spam, viruses and malware, leaving it unfiltered will land it in the user’s inbox. The effects of this email range from being a nuisance to a threat to the integrity of your organizational network. POP3 proxy’s mission is to filter all the emails that pass through it ensuring that your users’ inboxes stay as trouble free as possible.

The introduction material on email proxies shows that the system is comprised of three parts: the SMTP proxy, the POP3 proxy, and the scanning subsystem. This document is concerned about the setup and configuration of SMTP and POP3 proxies. Setting up, configuring and operating the scanning subsystem has a document of its own.