Firewall functions
Firewalls primarily have two functions:
- Packet filtering
- Network Address Translation
Most firewalls also perform two other important security services:
- Encrypted authentication
- Encrypted tunnels
Rules of a firewall
The rules of a firewall can be customized depending on our needs, requirements, and threat levels. There are different conditions on which firewall filters work. These are as follows:
- IP address: The first condition on which a firewall rule works is on IP address. The decision is based on the range of IP addresses and subnet masks.
- Domain name: The second condition on which a firewall works is on domain name. A firewall can be configured to permit or deny access to specified domain names of corporate websites or domain name extensions, such as
.org,.tv, or.biz. - Protocols and ports: The third condition a firewall works on is the protocols and its ports. A firewall can be configured to permit or deny some protocols and port numbers, such as SMTP, FTP, UDP, and SNMP. It...
