A common Transmission Control Protocol (TCP) port scan sends a TCP SYN (synchronize) packet to a specific port of a server as part of the TCP three-way handshake. If the server responds with a SYN/ACK (synchronize/acknowledge) packet, the scanner knows the port is open. However, instead of completing the three-way handshake, the scanner can send an RST (reset) packet to reset the connection and then repeat the process with a different port.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.