For a client request to a web server using Hypertext Transfer Protocol Secure (HTTPS), the refresher gives Transmission Control Protocol (TCP) port _____ as the destination port.

### Why this is right The refresher lists HTTPS with TCP port 443. In a client request, the server's service port is the destination port because the request is being sent to that server application. ### The concept A port number is a field in the transport header that helps a receiving device direct traffic to the right application. Common application-to-port associations are conventions used by servers and administrators. The refresher also lists HTTP on TCP port 80 and SSH on TCP port 22. These numbers do not themselves prove what a packet contains, and a sender is not prevented from using another port. ### Terms - **HTTPS**: Hypertext Transfer Protocol Secure. Encrypted web traffic. - **TCP**: Transmission Control Protocol. A transport protocol that supports reliable delivery. - **Port number**: A transport-header value that helps identify the receiving application. - **Destination port**: The port used to direct a packet to its receiving application. - **Transport header**: Packet information that includes fields such as source and destination ports. ### Remember For an HTTPS request to a server using the conventional port shown in the refresher, look for destination port 443.