ClamSMTP: An SMTP Virus Filter

ClamSMTP 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.


clamsmtpd(8): The man page.
clamsmtpd.conf(5): Man page for the config file.
Frequently Asked Questions


Mailing List
Subscribe/Unsubscribe | Archive


Source: clamsmtp-1.10.tar.gz
Source: clamsmtp-1.9.tar.gz
Source: clamsmtp-1.8.tar.gz
Source: clamsmtp-1.7.tar.gz
Source: clamsmtp-1.6.tar.gz
Source: clamsmtp-1.5.tar.gz
Source: clamsmtp-1.4.1.tar.gz
Source: clamsmtp-1.4.tar.gz [broken]
Source: clamsmtp-1.3.tar.gz
Source: clamsmtp-1.2.tar.gz
Source: clamsmtp-1.1.tar.gz
Source: clamsmtp-1.0.tar.gz
Source: clamsmtp-0.9.6.tar.gz
Source: clamsmtp-0.9.5.tar.gz
Source: clamsmtp-0.9.tar.gz
Source: clamsmtp-0.8.tar.gz
Source: clamsmtp-0.7.tar.gz
Source: clamsmtp-0.6.tar.gz
Source: clamsmtp-0.5.tar.gz
Source: clamsmtp-0.4.tar.gz [broken]
Source: clamsmtp-0.3.tar.gz [broken]
Source: clamsmtp-0.2.tar.gz [broken]


You can get a snapshot of the source with git:

$ git clone git://

Source code repository:

Third Party Contributions

VirusAction Scripts
ClamSMTP Stats Package [Nagy Gergely]
Fedora/Redhat init script [Martynas Bieliauskas]
Source RPMS [Martynas Bieliauskas]
Mandrake startup scripts [Michael Burger]
RPM Spec File [Rubio Vaughan]
SuSE Linux startup scripts [Jens Jacobsen]
Setting up ASSP+ClamSMTP for FCS (scripts) [Ray Saunders, World Scout Bureau]


FreeBSD Port
NetBSD Package
MacOS X Darwin Ports
Debian Package
Gentoo Ebuild

Licensing and Support

BSD type license. Contact the list when bugs are found.

   [ home page ]