Well Known (Common) Ports - 0-1023
FTP - TCP/UDP 20(data) and TCP 21(control)
File Transfer Protocol
SSH - TCP/UDP 22
Secure Shell
Telnet - TCP/UDP 23
SMTP - TCP 25
Simple Mail Transfer Protocol
DNS - TCP/UDP 53
Domain Name System
DHCP - UDP 67(IPv4 client) and UDP 68(IPv4 server);
TCP/UDP 546(IPv6 client) and TCP/UDP 547(IPv6 server)
Dynamic Host Configuration Protocol
TFTP - UDP 69
Trivial File Transfer Protocol
HTTP - TCP 80
Hypertext Transfer Protocol
Kerberos - TCP/UDP 88
Kerberos Authentication System
POP - TCP 110
Post Office Protocol
NTP - TCP 123
Network Time Protocol
NBNS - UDP/TCP 137