Today is the world of internet. You use many devices which use internet and run many tasks or programs at the same time. But tell me how will your device identify the coming message belongs to which program?
What is a port number?
Port number is a way to identify the destination program of the coming message or outgoing message. Port number is a 16-bit header which is put in TCP and UDP along with the message. Port numbers ranges from 0 to 65535.
What does port number do?
Port number tells your device that messages belongs to mail application or Whatsapp or YouTube etc. Without port number it would be difficult to understand the destination of the message within your device and multitasking would be impossible.
These ports are not physical. They are virtual and software based.They allow various applications to use same system resources.
The port number and IP address are used together. Imagine IP address is a house and people living in are ports. If a letter comes at the house address (IP address), the persons name (port number) is also mentioned on the letter.
Well Known Ports
|File Transfer Protocol (FTP) data transfer ||20|
|Domain Name System (DNS) ||53|
|Hypertext Transfer Protocol (HTTP) ||80, 8080|
|Post Office Protocol (POP3) ||110|
|Real Time Streaming Protocol (RTSP) ||7070|
|Simple Mail Transfer Protocol (SMTP) ||25|
|Dynamic Host Configuration Protocol (DHCP) ||67,68|
|Whatsapp ( its an application uses well known ports) ||80, 443, 4244, 5222, 5223, 5228 and 5242|
|Internet Message Access Protocol (IMAP)||143|
How do you find your port number?
You can find the port numbers your PC using by doing the following steps
- Click on “search tab” on taskbar of your windows PC
- Type “cmd” and press enter
- A command window will open. Type “netstat -a” and press enter. Wait for sometime then you will see the results something like below