Introduction to Network Security6 Firebox X Edge e-Series World Wide Web access uses Hypertext Transfer Protocol (HTTP) Email uses Simple Mail Transfer Protocol (SMTP) or Post Office Protocol (POP3) File transfer uses File Transfer Protocol (FTP) Resolving a domain name to an Internet address uses Domain Name Service (DNS) Remote terminal access uses Telnet or SSH (Secure Shell)When you allow or deny a service, you must add a policy to your Firebox configuration. Each policy you addcan also add a security risk. To send and receive data, you must open a door in your computer, which puts yournetwork at risk. We recommend that you add only the policies that are necessary for your business.About portsUsually, a port is a connection point where you use a jack and cables to connect devices. Computers also haveports that are not physical locations. These ports are where programs transmit data.Some protocols, such as HTTP, have ports with assigned numbers. For example, many computers transmitemail on port 110 because the POP3 protocol is assigned to port 110. Other programs are assigned portnumbers dynamically for each connection. The IANA (Internet Assigned Numbers Authority) keeps a list ofwell known ports. You can see this list at: http://www.iana.org/assignments/port-numbers.Most policies are given a port number in the range from 0 to 1024, but possible port numbers range from0 to 65535.
