ClamSMTP project is an SMTP filter that allows you to check for viruses using the ClamAV anti-virus software.
It accepts SMTP connections and forwards the SMTP commands and responses to another SMTP server. The 'DATA' email body is intercepted and scanned before forwarding.
ClamSMTP aims to be lightweight, reliable, and simple rather than have a myriad of options. It's written in C without major dependencies. If you need more options then you could use something big like AMaViS which is written in PERL and can do almost anything.
I wrote this with the Postfix mail server in mind. Here's how to configure it as a Postfix Content Filter.
ClamSMTP can also be used as a transparent proxy to filter an entire network's SMTP traffic at the router.
What's New in This Release:
· Support has been removed for listening on ports under 1024.
· Support has been added for embedded NULLs in email data.
· Problems with not listening properly when in daemon mode have been fixed, as well as warnings when compiled with gcc 4.0.
· Empty addresses are handled properly in logs.
· This release will not let Exchange send its strange binary data through the proxy.
· More Solaris fixes.
· Email messages are not rejected when the server is overloaded or encounters errors, or when starting the filter command fails.