ZyWALL 10/50 Internet Security Gateway

Step 3. Now you want to restrict access to the Internet except for the HTTP proxy server and your mail server. First you need to create a custom port for POP3. POP (Post Office Protocol) is an Internet mail server protocol that provides an incoming message storage system. It works in conjunction with the SMTP (Simple Mail Transfer Protocol), which provides the message transport services required to move mail from one system to another. The current version is called POP3. Click Custom Ports and then click Edit. Configure the screen as follows.

POP3 is now a predefined service, but you still use the same process forconfiguring a custom port.

Type a name for this

 

Click Single and enter

 

Click Apply when

custom port and select TCP

 

a port number of 110.

 

you’ve finished.

service.

 

 

 

 

 

 

 

 

 

Figure 16-7 Configuring A POP Custom Port

Step 4. Now, you will create rules to block all outgoing traffic (from the local network to the Internet) except for traffic originating from the HTTP proxy server and our mail server. Click Local

16-8

Example Firewall Rules