Nella seguente tabella vi è un elenco delle porte TCP / UDP più importanti con una relativa descrizione.
| Port | Service | Protocol | Class | Descrizione |
| 20 | ftp-data | TCP/UDP | Well-known | File Transfer Protocol (TCP) - Default Data |
| 21 | ftp-data | TCP/UDP | Well-known | File Transfer Protocol (TCP) - Control |
| 22 | ssh | TCP | Well-known | Secure Shell (SSH) - Remote Login Protocol |
| 23 | telnet | TCP | Well-known | Telnet |
| 25 | smtp | TCP | Well-known | Simple Mail Transfer Protocol (SMTP) |
| 53 | domain | TCP/UDP | Well-known | Domain Name Service (DNS) |
| 79 | finger | TCP | Well-known | Finger |
| 80 | http | TCP | Well-known | Hypertext Transfer Protocol (HTTP) |
| 98 | linuxconf | TCP | Well-known | linuxconf |
| 110 | pop3 | TCP | Well-known | Post Office Protocol Version 3 (POP3) |
| 111 | nfs | TCP | Well-known | NFS |
| 113 | ident | TCP | Well-known | ident |
| 119 | nntp | TCP | Well-known | Network News Transfer Protocol (NNTP) |
| 135 | rpc | TCP | Well-known | RPC |
| 137 | netbios-ns | TCP/UDP | Well-known | Netbios - Name Service |
| 138 | netbios-dgm | TCP/UDP | Well-known | Netbios - Datagram Service |
| 139 | netbios-ssn | TCP/UDP | Well-known | Netbios - Session Service (Win/SAMBA) |
| 143 | imap4 | TCP | Well-known | Internet Message Access Protocol Version 4 (IMAP4) |
| 389 | ldap | TCP | Well-known | Lightweight Directory Access Protocol (LDAP) |
| 443 | ssl | TCP | Well-known | Hypertext Transfer Protocol over TLS/SSL |
| 445 | microsoft-ds | TCP/UDP | Well-known | Microsoft Windows 2000/XP SMB |
| 554 | rtsp | TCP | Well-known | Real Time Stream Control Protocol |
| 636 | sldap | TCP | Well-known | Lightweight Directory Access Protocol over SSL |
| 901 | swat | TCP | Well-known | SWAT (SAMBA) |
| 993 | imaps | TCP | Well-known | Internet Message Access Protocol Version 4 over TLS/SSL |
| 995 | pop3s | TCP | Well-known | Post Office Protocol Version 3 over TLS/SSL |
| 1080 | proxy | TCP | Well-known | Proxy |
| 1214 | kazaa | TCP | Registered | Kazaa / Morpheus |
| 1755 | ms-streaming | TCP/UDP | Registered | Microsoft Media Player |
| 1863 | msnp | TCP | Registered | Microsoft MSN Messenger |
| 2302 - 2400 | unassigned | TCP | Registered | Microsoft DirectX 8 |
| 4661 | unassigned | TCP | Registered | Edonkey |
| 4662 | unassigned | TCP | Registered | Edonkey |
| 4665 | unassigned | TCP | Registered | Edonkey |
| 5050 | mmc | TCP | Registered | Multimedia Conference Control Tool |
| 5190 | aol | TCP | Registered | AOL Instant Messenger / Mirabilis ICQ |
| 6073 | directplay8 | TCP | Registered | Microsoft Direct Play 8 |
| 6112 | dtspcd | TCP/UDP | Registered | Battle.net |
| 6346 | gnutella-svc | TCP | Registered | Gnutella |
| 6347 | gnutella-rtr | TCP | Registered | Gnutella |
| 6667 | ircu | TCP | Registered | MSN Zone.com |
| 7070 | arcp | TCP | Registered | Real-Player-Server |
| 7071 | arcp | TCP | Registered | Real-Player-Server |
| 28800 - 29100 | unassigned | TCP | Registered | MSN Zone.com |