| 20 | File Transfer Protocol (FTP) Data Transfer |
| 21 | File Transfer Protocol (FTP) Command Control |
| 22 | Secure Shell (SSH) Secure Login |
| 23 | Telnet remote login service, unencrypted text messages |
| 25 | Simple Mail Transfer Protocol (SMTP) email delivery |
| 53 | Domain Name System (DNS) service |
| 67, 68 | Dynamic Host Configuration Protocol (DHCP) |
| 80 | Hypertext Transfer Protocol (HTTP) used in the World Wide Web |
| 110 | Post Office Protocol (POP3) |
| 119 | Network News Transfer Protocol (NNTP) |
| 123 | Network Time Protocol (NTP) |
| 143 | Internet Message Access Protocol (IMAP) Management of digital mail |
| 161 | Simple Network Management Protocol (SNMP) |
| 194 | Internet Relay Chat (IRC) |
| 443 | HTTP Secure (HTTPS) HTTP over TLS/SSL |
| 546, 547 | DHCPv6 IPv6 version of DHCP |