A user on the LAN can configure an email client in order to connect to an external POP3 server and download mail messages. However, fetched mail could contain viruses that may infect computer on the network.
The POP3 proxy intercepts connection to external servers on port 110, then it scans all incoming email, in order to block viruses and tag spam. The process is absolutely transparent to mail clients: the user believes to connect directly to the provider’s POP3 server, but the proxy will intercept all traffic and handle the connection to the server.
It’s possible to selectively activate following controls:
- antivirus: messages containing virus are rejected and a notification email is sent to the user
- spam: messages will be marked with the appropriate anti-spam scores
The proxy can also intercept POP3s connections on port 995. The proxy will establish a secure connection to the external server, but data exchange with LAN client will be in the clear text.
Mail clients must be configured to connect to port 995 but will have to turn off encryption.