How Many Ports of TCP/IP Are Reserved for Specific Protocols?

TCP/IP is the foundation of the internet. It is responsible for routing and delivering data packets between different devices, but it has limitations. The IP layer can only identify machines, and it doesn’t have a system to identify services running on those machines. This is where the TCP layer comes in. It adds another level of addressing to the IP layer, creating connections and identifying services running on a server.

Let’s say your computer is communicating with a web server. The server is running multiple services, such as a website, secure shell server, and an email server. Each of these services requires a way to identify which server the client wants to interact with. TCP introduces something called ports. TCP ports are numbers that identify each connection made over TCP.

Each connection made over TCP has a port number on each side of it. The port numbers are unique throughout the lifetime of the connection. For example, a client might make five connections to a web server, each with a unique port number, such as 1,001, 1,002, 1,003, 1,004, and 1,005. The server sends different parts of the page to the client on the TCP connection that’s been established with the client listening on each of these ports.

The client also tells the server what port it wants to connect to when it opens a TCP connection. There are well-known ports that allow the client to indicate what type of service it wants to interact with. For example, if you want to talk to a web server, you initiate a connection on port 80. If you want to talk to an ssh server, you initiate a connection on port 22. These well-known port numbers allow the client to make sure that it knows how to interact with the server.

TCP ports are an additional level of naming that’s been layered on top of the IP layer. It provides a way to establish multiple connections to the same server and to make sure those connections don’t intermingle with each other. The IP layer, on the other hand, only thinks that it’s delivering packets from one host to another host. The TCP layer is in charge of separating traffic that’s destined for different ports both on the client and on the server.

In conclusion, TCP ports are a crucial part of the TCP/IP protocol. They allow multiple connections to be established between a client and a server, and they ensure that data can be correctly reassembled without intermingling. Understanding TCP ports and their well-known numbers is essential for anyone who wants to interact with the internet on a deeper level.