The following items needs to be considered when using clamsmtp:

1. Scanning is done via clamd (clamav-daemon)

   The clamd daemon must be running for scanning to take place.

2. Transparent proxy

   For transparent proxying you need an IP tables rule such as:

     iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 25 -j REDIRECT --to-ports 10025

   where eth0 is the incomming port, and 10025 is the port that clamsmtpd
   is running on. Also remember to enable transparent proxy support in the
   configuration file.