Commonly used TCP and UDP Ports
DNS / Domain Name Services
TCP & UDP Port 53
HTTP / Hypertext Transfer Protocol
TCP & UDP Port 80
POP3 / Post Office Protocol v3
TCP Port 110
IMAP / Internet Message Access Protocol
TCP Port 143
FTP (data) / File Transfer Protocol
TCP Port 20
FTP (control) / File Transfer Protocol
TCP Port 21
SSH / Secure Shell
TCP Port 22
Telnet / Telecommunication Network
TCP Port 23
SMTP / Simple Mail Transfer Protocol
TCP Port 25
HTTPS / Hypertext Transfer Protocol Secure
TCP Port 443
NTP / Network Time Protocol
UDP Port 123
SNMP v1, 2, & 3 / Simple Network Management Protocol versions 1, 2, & 3
UDP Port 161
BOOTP & DHCP / Bootstrap and Dynamic Host Configuration Protocol
UDP Port 67
TFTP / Trivial File Transfer Protocol
UDP Port 69
Ephemeral Ports
In TCP/IP communication, an arbitrary number generated by a sending computer that the receiving computer uses as a destination address when sending a return packet.
