What Service Has Source Port 51523 And Destination Port 80

What is a TCP port?

The TCP port is a unique number assigned to different applications. For example, nosotros have opened the email and games applications on our reckoner; through electronic mail application, we desire to send the post to the host, and through games awarding, we want to play the online games. In gild to do all these tasks, different unique numbers are assigned to these applications. Each protocol and address take a port known as a port number. The TCP (Manual Control Protocol) and UDP (User Datagram Protocol) protocols mainly use the port numbers.

A port number is a unique identifier used with an IP address. A port is a sixteen-bit unsigned integer, and the total number of ports available in the TCP/IP model is 65,535 ports. Therefore, the range of port numbers is 0 to 65535. In the case of TCP, the zero-port number is reserved and cannot be used, whereas, in UDP, the naught port is non bachelor. IANA (Internet Assigned Numbers Authority) is a standard body that assigns the port numbers.

Instance of port number:

192.168.1.100: vii

In the above case, 192.168.one.100 is an IP address, and vii is a port number.

To access a item service, the port number is used with an IP address. The range from 0 to 1023 port numbers are reserved for the standard protocols, and the other port numbers are user-defined.

Why exercise we crave port numbers?

A single client tin have multiple connections with the same server or multiple servers. The customer may be running multiple applications at the same time. When the customer tries to admission some service, then the IP address is not sufficient to access the service. To access the service from a server, the port number is required. So, the transport layer plays a major office in providing multiple advice between these applications by assigning a port number to the applications.

Classification of port numbers

The port numbers are divided into 3 categories:

Well-known ports
Registered ports
Dynamic ports

Well-known ports

The range of well-known port is 0 to 1023. The well-known ports are used with those protocols that serve common applications and services such as HTTP (hypertext transfer protocol), IMAP (Internet Message Admission Protocol), SMTP (Simple Mail Transfer Protocol), etc. For example, we want to visit some websites on an internet; then, we use http protocol; the http is available with a port number eighty, which means that when we use http protocol with an application and so information technology gets port number lxxx. It is divers that whenever http protocol is used, then port number 80 will exist used. Similarly, with other protocols such as SMTP, IMAP; well-known ports are defined. The remaining port numbers are used for random applications.

Registered ports

The range of registered port is 1024 to 49151. The registered ports are used for the user processes. These processes are private applications rather than the mutual applications that take a well-known port.

Dynamic ports

The range of dynamic port is 49152 to 65535. Another name of the dynamic port is ephemeral ports. These port numbers are assigned to the customer application dynamically when a customer creates a connection. The dynamic port is identified when the client initiates the connection, whereas the client knows the well-known port prior to the connection. This port is non known to the customer when the client connects to the service.

TCP and UDP header

Equally we know that both TCP and UDP comprise source and destination port numbers, and these port numbers are used to identify the application or a server both at the source and the destination side. Both TCP and UDP use port numbers to laissez passer the information to the upper layers.

Allow's understand this scenario.

Suppose a client is accessing a web folio. The TCP header contains both the source and destination port.

Client-side

In the above diagram,

Source Port: The source port defines an application to which the TCP segment belongs to, and this port number is dynamically assigned by the client. This is basically a procedure to which the port number is assigned.

Destination port: The destination port identifies the location of the service on the server so that the server can serve the request of the client.

Server-side

In the above diagram,

Source port: It defines the awarding from where the TCP segment came from.

Destination port: It defines the application to which the TCP segment is going to.

In the higher up case, 2 processes are used:

Encapsulation: Port numbers are used by the sender to tell the receiver which application it should apply for the data.

Decapsulation: Port numbers are used by the receiver to identify which application should it sends the data to.

Allow's understand the above instance past using all 3 ports, i.e., well-known port, registered port, and dynamic port.

First, we look at a well-known port.

The well-known ports are the ports that serve the common services and applications like http, ftp, smtp, etc. Here, the client uses a well-known port as a destination port while the server uses a well-known port equally a source port. For instance, the client sends an http request, then, in this case, the destination port would be 80, whereas the http server is serving the request so its source port number would be lxxx.

Now, nosotros await at the registered port.

The registered port is assigned to the not-common applications. Lots of vendor applications utilize this port. Like the well-known port, client uses this port as a destination port whereas the server uses this port as a source port.

At the terminate, we see how dynamic port works in this scenario.

The dynamic port is the port that is dynamically assigned to the customer application when initiating a connection. In this instance, the client uses a dynamic port as a source port, whereas the server uses a dynamic port as a destination port. For case, the client sends an http asking; so in this case, destination port would exist lxxx as information technology is a http request, and the source port will only exist assigned past the client. When the server serves the asking, and so the source port would be 80 as it is an http server, and the destination port would be the same as the source port of the customer. The registered port tin can also be used in place of a dynamic port.

Allow's look at the below example.

Suppose client is communicating with a server, and sending the http request. Then, the customer sends the TCP segment to the well-known port, i.due east., 80 of the HTTP protocols. In this case, the destination port would be 80 and suppose the source port assigned dynamically past the client is 1028. When the server responds, the destination port is 1028 as the source port defined by the client is 1028, and the source port at the server cease would exist eighty as the HTTP server is responding to the request of the client.