Common Protocols and Ports (for Hackers)
Common TCP/IP Protocols and Ports File Transfer Protocol (FTP) (RFC 959) TCP 20/21 FTP is one of the most commonly used file transfer protocols on the Internet and within private networks. An FTP server can easily be set up with little networking knowledge and provides the ability to easily relocate files from one system to another. FTP control is handled on TCP port 21 and its data transfer can use TCP port 20 as well as dynamic ports depending on the specific configuration. Secure Shell (SSH) (RFC 4250-4256) TCP 22 SSH is the primary method used to manage network devices securely at the command level. It is typically used as a secure alternative to Telnet which does not support secure connections. Telnet (RFC 854) TCP 23 Telnet is the primary method used to manage network devices at the command level. Unlike SSH which provides a secure connection, Telnet does not, it simply provides a basic unsecured connection. Many lower level network devices support Telnet and not SSH as it requi