🛠️ Common Ports & Protocols Cheat Sheet
A quick reference for well-known TCP/UDP ports and their usage. Useful for students, professionals, and anyone studying for certifications like CCNA, CompTIA, or Security+.
📌 Well-Known / System Ports (0 – 1023)
| Port | Service | Protocol | Description |
|---|---|---|---|
| 7 | Echo | TCP, UDP | Echo service |
| 19 | CHARGEN | TCP, UDP | Character Generator Protocol (rarely used, vulnerable) |
| 20 | FTP-data | TCP, SCTP | File Transfer Protocol (data) |
| 21 | FTP | TCP, UDP, SCTP | File Transfer Protocol (control) |
| 22 | SSH/SCP/SFTP | TCP, UDP, SCTP | Secure Shell, secure logins, file transfers, port forwarding |
| 23 | Telnet | TCP | Unencrypted text communication |
| 25 | SMTP | TCP | Simple Mail Transfer Protocol (email routing) |
| 53 | DNS | TCP, UDP | Domain Name System |
| 67 | DHCP/BOOTP | UDP | DHCP Server |
| 68 | DHCP/BOOTP | UDP | DHCP Client |
| 69 | TFTP | UDP | Trivial File Transfer Protocol |
| 80 | HTTP | TCP, UDP, SCTP | Web traffic (HTTP/1.x, HTTP/2 over TCP; HTTP/3 uses QUIC/UDP) |
| 88 | Kerberos | TCP, UDP | Network authentication system |
| 110 | POP3 | TCP | Post Office Protocol (email retrieval) |
| 123 | NTP | UDP | Network Time Protocol |
| 135 | Microsoft RPC EPMAP | TCP, UDP | Remote Procedure Call Endpoint Mapper |
| 137-139 | NetBIOS | TCP, UDP | NetBIOS services (name service, datagram, session) |
| 143 | IMAP | TCP, UDP | Internet Message Access Protocol |
| 161-162 | SNMP | UDP | Simple Network Management Protocol (unencrypted) |
| 179 | BGP | TCP | Border Gateway Protocol |
| 389 | LDAP | TCP, UDP | Lightweight Directory Access Protocol |
| 443 | HTTPS | TCP, UDP, SCTP | Secure web traffic (SSL/TLS) |
| 445 | Microsoft DS SMB | TCP, UDP | File sharing, Active Directory |
| 465 | SMTPS | TCP | SMTP over SSL/TLS |
| 514 | Syslog | UDP | System log protocol |
| 520 | RIP | UDP | Routing Information Protocol |
| 546-547 | DHCPv6 | UDP | DHCP for IPv6 (client/server) |
| 636 | LDAPS | TCP, UDP | LDAP over SSL |
| 993 | IMAPS | TCP | IMAP over SSL/TLS |
| 995 | POP3S | TCP, UDP | POP3 over SSL/TLS |
📌 Registered Ports (1024 – 49151)
| Port | Service | Protocol | Description |
|---|---|---|---|
| 1025 | Microsoft RPC | TCP | RPC service |
| 1080 | SOCKS proxy | TCP, UDP | Proxy protocol |
| 1194 | OpenVPN | TCP, UDP | VPN tunneling |
| 1433 | MS-SQL Server | TCP | Microsoft SQL Server |
| 1521 | Oracle DB | TCP | Oracle Database listener |
| 1701 | L2TP | TCP | Layer 2 Tunneling Protocol |
| 1720 | H.323 | TCP | VoIP signaling |
| 1723 | PPTP | TCP, UDP | VPN protocol (deprecated) |
| 1812-1813 | RADIUS | UDP | Authentication, accounting |
| 2049 | NFS | UDP | Network File System |
| 2082-2083 | cPanel | TCP, UDP | Web hosting control panel |
| 2222 | DirectAdmin | TCP | Hosting control panel |
| 2483-2484 | Oracle DB | TCP, UDP | Insecure & SSL listener |
| 3074 | Xbox Live | TCP, UDP | Online gaming |
| 3128 | HTTP Proxy | TCP | Common proxy port |
| 3260 | iSCSI Target | TCP, UDP | Storage protocol |
| 3306 | MySQL | TCP | Database system |
| 3389 | RDP | TCP | Windows Remote Desktop |
| 3690 | SVN | TCP, UDP | Apache Subversion |
| 3724 | World of Warcraft | TCP, UDP | Gaming |
| 4333 | mSQL | TCP | Mini SQL |
| 4444 | Blaster Worm | TCP, UDP | Malware |
| 5000 | UPnP | TCP | Universal Plug & Play |
| 5060-5061 | SIP | TCP, UDP | Session Initiation Protocol (VoIP) |
| 5222-5223 | XMPP | TCP, UDP | Messaging protocol |
| 5432 | PostgreSQL | TCP | Database system |
| 5900-5999 | VNC | TCP, UDP | Remote desktop (VNC) |
| 6379 | Redis | TCP | In-memory database |
| 6665-6669 | IRC | TCP | Internet Relay Chat |
| 6881-6999 | BitTorrent | TCP, UDP | File sharing |
| 8080 | HTTP Proxy/Alt | TCP | Alternate web port |
| 8443 | HTTPS Alt | TCP | Alternate secure web port |
| 9042 | Cassandra | TCP | NoSQL database |
| 9100 | Printer (PDL) | TCP | Print Data Stream |
📌 Dynamic / Private Ports (49152 – 65535)
These are used for ephemeral connections and custom apps. Safe to use for internal development/testing.
🎯 Most Common Ports for Exams
If you’re preparing for CCNA / CompTIA exams, focus on these:
| Port | Service |
|---|---|
| 7 | Echo |
| 20, 21 | FTP |
| 22 | SSH/SCP |
| 23 | Telnet |
| 25 | SMTP |
| 53 | DNS |
| 67, 68 | DHCP |
| 69 | TFTP |
| 80 | HTTP |
| 88 | Kerberos |
| 110 | POP3 |
| 123 | NTP |
| 137-139 | NetBIOS |
| 143 | IMAP |
| 161, 162 | SNMP |
| 389 | LDAP |
| 443 | HTTPS |
| 445 | SMB |
| 636 | LDAPS |
| 3389 | RDP |
| 5060-5061 | SIP (VoIP) |
✅ Conclusion
Familiarity with ports & protocols is essential for:
- Building secure applications
- Troubleshooting network issues
- Passing certification exams
Keep this cheat sheet handy as a quick reference!