Before we discuss firewalls in detail, you must understand the basic terminology:
- IP Address: An IP address is a host identity on the internet through which reachability is achieved via a routing protocol between networks. There are two types of IP address available—IPv4 (32 bit with class A, B, C, or D) and IPv6 (128 bit with unicast address, any cast address, or multicast address). For example, IPv4: 200.10.20.1 and IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
- Ports: Any application that is hosted on an operating system makes its service available on a network using standard ports. When accessing any application on the internet, a dynamic port is opened on source and a standard known port for destination. For example, ...
