PDF file: common_ports by Jeremy Stretch, via packetlife.net
Category: Ports
What is RDP?
Remote Desktop Protocol: A Microsoft protocol that allows a user to view and control the desktop of a remote computer TCP Port 3389
What is NTP?
Network Time Protocol: Used by a network device to synchronize its clock with a time server (NTP server) UDP Port 123
What is HTTP?
Hypertext Transfer Protocol: Retrieves content from a web server TCP Port 80
What is NetBIOS?
Network Basic Input/Output System: Provides network communication services for LANs that use NetBIOS TCP Port 139 UDP Port 137, 138
What is DNS?
Domain Name System: Resolves domain names to corresponding IP addresses TCP Port 53 UDP Port 53
What is Telnet?
Telnet: Used to connect to a remote host (typically via a terminal emulator) TCP Port 23
What is SSH?
Secure Shell: Securely connect to a remote host (typically via a terminal emulator) TCP Port : 22
What is FTP?
File Transfer Protocol: Transfers files with a remote host (typically requires authentication of user credentials). TCP Port 20 and 21