In computer networking, the port number is a component of the addressing information that is used to identify message senders and recipients. To specify which protocol inbound traffic should be forwarded to, several port numbers are utilised. When a network communication from the Internet or another source reaches a server, the port number identifies the precise process to which it should be passed. Each protocol has a set of defined ports, which are regarded as communication endpoints.
Ports are represented by 16-bit numbers. There are 2^16 port numbers i.e 65536.
Three categories have been established.
1. Well-Known Port Numbers
0 to 1023 are well-known port numbers are as they are used by well-known protocol services.
These are allocated to server services by the Internet Assigned Numbers Authority (IANA).
2. Registered Port Numbers
1024 to 49151 are registered port numbers i.e it can be registered to specific protocols by software corporations
3. Dynamic Port Numbers
49152 to 65535 are dynamic port numbers and they can be used by anyone
