Ports and Application tutorials

  • Two protocols functions at the Host to Host (TRANSPORT) layer: TCP and UDP

  • When an application wants to establish communication with an application on a remote host, it creates a TCP or UDP socket.

  • It is not necessary to configure application to use specific Ports, however you should know following when you configure Firewall inbound and outbound rules.

TCP and UDP Protocol Working




Stands for Transmission Control Protocol

Stands for User Datagram Protocol

TCP takes large blocks of information from an application and breaks them into segment. It numbers and sequences each segment so that the destination TCP can put those segments back into the order. After these segments are sent, it waits for an acknowledgement. It resends anything that is not received.

UDP does not sequence the segment and does not care in which order the segments arrive at the destination. After it sends the segment it forgets about it and do not acknowledge it.


It is connection oriented

Because does not contact the destination before delivering information to it, it is considered as connectionless protocol.

It is Reliable & Accurate

It is fast but unreliable.

As it checks for error, it is complicated and costly in terms of network overhead.

It is simple and does not increase network overhead.



Port Numbers

  • Port numbers are assigned by the IANA (Internet Assigned Numbers Authority).

  • In all there are 65,536 ports. Port receives number from 0 to 65,535.

  • Numbers 0 to 1,023 are considered Well-known ports.

  • Numbers 1,024 to 49,151 are Registered Ports.

  • Number 49,152 to 65,535 are Private vendor assigned and are dynamic.