The following items needs to be considered when using clamsmtp:

1. 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 8110
     iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 110 -j REDIRECT --to-ports 8110
     iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 995 -j REDIRECT --to-ports 8110

   where eth0 is the incomming port, and 8110 is the port that p3scan is
   running on. Also remember to enable transparent proxy support in the
   configuration file.

   The ports are 25 for smtp, 110 for pop3 and 995 for pop3s.