Application Port Numbers

Question 1

What do TCP use source and destination ports for?

Answer 1

To keep track of application conversations.

They are used to identify the applications which should handle the data.

Question 2

What are source and destination ports?

Answer 2

The source port number is associatd with the originating application on the local device.
The destination port is associated with the destination application on the remote deivce.
These are not physical ports.

Question 3

What does each port have?

Answer 3

A port number.
At least one relevant transport protocol of TCP or UDP.
An associated application protocol suhc as HTTP.

Question 4

How is the source port number generated?

Answer 4

Dynamically, so that the source port cn handle multiple conversations at a time.
An example of this in action would be the opening of multiple tabs at a time.

Question 5

What are the port numbers 80 and 443 used for?

Answer 5

Web traffic and secure web traffic.

HTTP and HTTPS.

Question 6

What transport protocols do ports 53 use? 80? 443?

Answer 6

TCP/UDP.
TCP.
TCP/UDP.

Question 7

What transport protocols do ports 25 use? 110? 143? 389?

Answer 7

TCP.
TCP.
TCP.
TCP/UDP.

Question 8

What transport protocols do ports 20 use? 21? 69? 445? 548?

Answer 8

TCP.
TCP.
UDP.
TCP.
TCP/UDP.

Question 9

What transport protocols do ports 22 use? 23? 3389?

Answer 9

TCP.
TCP.
TCP/UDP.