Common TCP/IP Protocols and Ports
| Protocol | TCP/UDP | Port Number |
| File Transfer Protocol (FTP)
(RFC 959) |
TCP | 20/21 |
| Secure Shell (SSH)
(RFC 4250-4256) |
TCP | 22 |
| Telnet
(RFC 854) |
TCP | 23 |
| Simple Mail Transfer Protocol (SMTP)
(RFC 5321) |
TCP | 25 |
| Domain Name System (DNS)
(RFC 1034-1035) |
TCP/UDP | 53 |
| Dynamic Host Configuration Protocol (DHCP)
(RFC 2131) |
UDP | 67/68 |
| Trivial File Transfer Protocol (TFTP)
(RFC 1350) |
UDP | 69 |
| Hypertext Transfer Protocol (HTTP)
(RFC 2616) |
TCP | 80 |
| Post Office Protocol (POP) version 3
(RFC 1939) |
TCP | 110 |
| Network Time Protocol (NTP)
(RFC 5905) |
UDP | 123 |
| NetBIOS
(RFC 1001-1002) |
TCP/UDP | 137/138/139 |
| Internet Message Access Protocol (IMAP)
(RFC 3501) |
TCP | 143 |
| Simple Network Management Protocol (SNMP)
(RFC 1901-1908, 3411-3418) |
TCP/UDP | 161/162 |
| Border Gateway Protocol (BGP)
(RFC 4271) |
TCP | 179 |
| Lightweight Directory Access Protocol (LDAP)
(RFC 4510) |
TCP/UDP | 389 |
| Hypertext Transfer Protocol over SSL/TLS (HTTPS)
(RFC 2818) |
TCP | 443 |
| Lightweight Directory Access Protocol over TLS/SSL (LDAPS)
(RFC 4513) |
TCP/UDP | 636 |
| FTP over TLS/SSL
(RFC 4217) |
TCP | 989/990 |
The complete list of assigned ports and their assigned services can be seen at http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml.