Some open-source projects made by Frank DENIS.


A bridge between Qmail and the Sophos antivirus

The Qmail virus scanner (QScan) is a mail filter for Qmail that scans incoming messages using the Sophos Antivirus engine, immediately rejecting infected content.


As virus scanning is a CPU-intensive operation, QScan tries to be smart and enforces a concurrency limit. By default, only 10 mails are scanned for virus at the same time. It doesn’t mean that you can’t receive more simultanous mails, though. You can receive an unlimited number of mails coming from the local network, and an unlimited number of mails without attachments from the network.

But mails coming from a remote source with suspect attachments will be a bit delayed if already 10 scanners are currently running. It’s a preventive mesure against unwanted CPU hogs.

If your system is fast enough, you can raise the limit with the —with-concurrency switch passed to the ‘configure’ script. For instance :

./configure —with-concurrency=10

On the other hand, on low-end personal machines, you can lower that limit down to 1.