Below are the most well know TCP/UDP ports
View IANA for the full list of all ports.
| Protocol | Layer / Type | Default port(s) | Transport | Very short description |
|---|---|---|---|---|
| HTTP | Application (web) | 80 | TCP | Unencrypted web traffic and APIs. |
| HTTPS | Application (web) | 443 | TCP | TLS‑encrypted web traffic and APIs. |
| HTTP/3 | Application (web) | 443 | UDP (QUIC) | Web over QUIC using UDP. |
| DNS | Application (naming) | 53 | UDP/TCP | Resolves names to IP addresses. |
| DHCP | Application (config) | 67 (server), 68 (client) | UDP | Automatically assigns IPv4 config. |
| DHCPv6 | Application (config) | 546 (client), 547 (server) | UDP | Automatically assigns IPv6 config. |
| NTP | Application (time) | 123 | UDP | Synchronizes clocks over IP. |
| SMTP | Application (email) | 25, 587 | TCP | Mail submission and relay. |
| SMTPS (implicit) | Application (email) | 465 | TCP | TLS‑wrapped SMTP (legacy but widely used). |
| POP3 | Application (email) | 110 | TCP | Retrieves email from server. |
| POP3S | Application (email) | 995 | TCP | TLS‑encrypted POP3. |
| IMAP | Application (email) | 143 | TCP | Accesses mailboxes on server. |
| IMAPS | Application (email) | 993 | TCP | TLS‑encrypted IMAP. |
| FTP (control) | Application (file) | 21 | TCP | Legacy file transfer control channel. |
| FTP (data) | Application (file) | 20 (active) | TCP | Legacy FTP data channel. |
| TFTP | Application (file) | 69 | UDP | Trivial file transfer, no auth. |
| FTPS | Application (file) | 990 (implicit) | TCP | FTP with TLS security. |
| SFTP | Application (file) | 22 | TCP | File transfer subsystem over SSH. |
| SSH | Application (remote) | 22 | TCP | Secure remote shell and tunneling. |
| Telnet | Application (remote) | 23 | TCP | Unencrypted remote terminal. |
| RDP | Application (remote) | 3389 | TCP/UDP | Remote desktop for Windows systems. |
| VNC | Application (remote) | 5900 | TCP | Remote desktop sharing protocol. |
| LDAP | Application (directory) | 389 | TCP/UDP | Directory and identity queries. |
| LDAPS | Application (directory) | 636 | TCP | TLS‑encrypted LDAP. |
| Kerberos | Application (auth) | 88 | TCP/UDP | Ticket‑based network authentication. |
| RADIUS | Application (auth) | 1812 (auth), 1813 (acct) | UDP | AAA for network access. |
| Syslog | Application (logging) | 514 | UDP (TCP also used) | Centralized log message transport. |
| IRC | Application (chat) | 6667 (default) | TCP | Legacy text chat protocol. |
| MQTT | Application (IoT) | 1883, 8883 (TLS) | TCP | Lightweight pub/sub for IoT. |
| SIP | Application (VoIP) | 5060, 5061 (TLS) | TCP/UDP | Session control for VoIP calls. |
| RTP | Application (media) | Dynamic (often 16384–32767) | UDP | Real‑time media transport. |
| RTSP | Application (stream) | 554 | TCP/UDP | Controls streaming media sessions. |
| OpenVPN | Application (VPN) | 1194 | UDP/TCP | SSL/TLS‑based VPN tunnels. |
| IPsec (IKE) | Key mgmt (VPN) | 500 (IKE), 4500 (NAT‑T) | UDP | Key exchange for IPsec tunnels. |
| L2TP | Tunneling (VPN) | 1701 | UDP | Layer‑2 tunneling, often with IPsec. |
| WireGuard | VPN | 51820 (default) | UDP | Modern, minimal VPN protocol. |
| mDNS | Service discovery | 5353 | UDP | Multicast DNS for local discovery. |
| SSDP | Service discovery | 1900 | UDP | UPnP device discovery. |