IP addresses are addresses that help to uniquely identify a device over the internet. A port is an endpoint for communication in an operating system.

When you connect to the internet, your device is assigned a public IP address, and each website you visit also has a public IP address. So far, we have used IPv4 as an addressing system. The main problem with this is that the internet is running out of IPv4 public address space and so it is necessary to introduce IPv6, which provides a larger address space. 

The following are the addresses for total IPv4 and IPv6 space:

• Total IPv4 space: 4, 294, 967, 296 addresses
• Total IPv6 space: 340, 282, 366, 920, 938, 463, 463, 374, 607, 431, 768, 211, 456 addresses

The ports are numerical values (between 0 and 65, 535) that are used to identify the processes that are being communicated. At each end, each process that intervenes in the communication process uses a single port to send and receive data.

In conjunction with this, two pairs of ports and IP addresses, you can identify two processes in a TCP/IP network. A system might be running thousands of services, but to uniquely identify a service on a system, the application requires a port number.

Port numbers are sometimes seen on the web or other URLs as well. By default, HTTP uses port 80, and HTTPS uses port 443, but a URL like http://www.domain.com:8080/path/ specifies that the web browser, instead of using default port 80, is connecting to port 8080 of the HTTP server.

Some common ports are as follows:

• 22: Secure Shell (SSH)
• 23: Telnet remote login service
• 25: SMTP
• 53: Domain Name System (DNS) service
• 80: HTTP

Regarding IP addresses, we can differentiate two types, depending on whether they are for a public or private rank for the internal network of an organization:

• Private IP address: Ranges from 192.168.0.0 to 192.168.255.255, 172.16.0.0 to 172.31.255.255, or 10.0.0.0 to 10.255.255.255
• Public IP address: A public IP address is an IP address that your home or business router receives from your Internet Service Provider (ISP)