TCP/IP

TCP/IP hijacking is a clever technique that uses spoofed packets to take over a connection between a victim and a host machine. This technique is exceptionally useful when the victim uses a one-time password to connect to the host machine. A one-time password can be used to authenticate once and only once, which means that sniffing the authentication is useless for the attacker.

When your web browser or email program connects to another computer on the Internet, it does so through a TCP/IP port. If you have a web server or FTP server running on your computer, it opens a port to which other computers can connect. Port numbers are used to distinguish one network service from another.