qSheff is an advanced content filter for the qmail e-server. It can scan for viruses and spams. qSheff replaces qmail-queue and gets the e-mails received by qmail-smtpd or qmail-inject before qmail-queue. After scanning the content, if the e-mail is allowed, qSheff releases it to the queue and allows it to go on-route. By intercepting e-mails before they enter the queue, qSheff reduces the e-mail server load.
qSheff has more features than alternative content filters and performs better. qSheff's most important features are:
Direct connection to ClamAv Antivirus daemon over socket.
Executing antivirus program
Filtering by header lines.
Filtering by body.
Filtering by header lines.
Regular expressions support.
Attachment blocking by filenames and extensions
White/Black list support (network, IP, domain and e-mail address based blocking or permitting)
Could save all incoming/outgoing mail trafic or just rejected emails
Single line logging
Blackhole -- option to return nothing when a virus or spam is found
Custom message return option instead of qmail "permanently" error.
Subject tagging for spam mails.
Could filter or skip local users.
Supporting qmailqueue patch.
Blocking e-mails of broken headers
Easy installation by the GNU autotools
Monitoring SPAM traffic with MRTG
Extendable, fast and simple code
Easy debugging, bug tracking