Common Port Numbers: The Complete Reference Table
Network ports are virtual endpoints that identify specific processes or services on a host. When data arrives at an IP address, the port number tells the operating system which application should receive it. Think of the IP address as the building address and the port number as the apartment number. This reference covers the most important ports you’ll encounter in networking, security, and system administration.
Well-Known Ports (0 to 1023)
These are assigned by IANA to common protocols and services. They require root/administrator privileges to bind on most operating systems.
Essential Web & Transfer Ports
| Port | Protocol | Service | Notes |
|---|---|---|---|
| 20 | TCP | FTP Data | File transfer data channel |
| 21 | TCP | FTP Control | File transfer commands |
| 22 | TCP | SSH | Secure shell, SCP, SFTP |
| 23 | TCP | Telnet | Unencrypted remote access (don’t use) |
| 25 | TCP | SMTP | Email sending |
| 53 | TCP/UDP | DNS | Domain name resolution |
| 67/68 | UDP | DHCP | IP address assignment |
| 69 | UDP | TFTP | Trivial file transfer |
| 80 | TCP | HTTP | Unencrypted web traffic |
| 110 | TCP | POP3 | Email retrieval |
| 123 | UDP | NTP | Time synchronization |
| 143 | TCP | IMAP | Email retrieval (better than POP3) |
| 161/162 | UDP | SNMP | Network monitoring |
| 389 | TCP | LDAP | Directory services |
| 443 | TCP | HTTPS | Encrypted web traffic |
| 445 | TCP | SMB | Windows file sharing |
| 465 | TCP | SMTPS | Encrypted email sending (deprecated, use 587) |
| 514 | UDP | Syslog | System logging |
| 587 | TCP | SMTP Submission | Email sending with STARTTLS |
| 636 | TCP | LDAPS | Encrypted LDAP |
| 993 | TCP | IMAPS | Encrypted IMAP |
| 995 | TCP | POP3S | Encrypted POP3 |
Database Ports
| Port | Protocol | Service |
|---|---|---|
| 1433 | TCP | Microsoft SQL Server |
| 1521 | TCP | Oracle Database |
| 3306 | TCP | MySQL / MariaDB |
| 5432 | TCP | PostgreSQL |
| 6379 | TCP | Redis |
| 27017 | TCP | MongoDB |
Application & Service Ports
| Port | Protocol | Service |
|---|---|---|
| 3389 | TCP | RDP (Remote Desktop) |
| 5060/5061 | TCP/UDP | SIP (VoIP) |
| 5900 | TCP | VNC |
| 8080 | TCP | HTTP alternative / proxy |
| 8443 | TCP | HTTPS alternative |
| 9090 | TCP | Web management interfaces |
| 51820 | UDP | WireGuard VPN |
VPN & Tunnel Ports
| Port | Protocol | Service |
|---|---|---|
| 500 | UDP | IKEv2/IPSec |
| 1194 | UDP/TCP | OpenVPN |
| 1723 | TCP | PPTP (don’t use) |
| 4500 | UDP | IPSec NAT-T |
| 51820 | UDP | WireGuard |
Port Security
Open ports are potential attack vectors. Security best practices:
- Close all ports that aren’t actively needed
- Firewall rules should default to deny with explicit allows
- Don’t expose database ports to the internet
- Use non-standard ports for SSH (change from 22 to reduce automated attacks)
- Monitor open ports with regular scans
Test It Yourself
Port Scanner
Scan any host for open TCP ports. See which services are running and potentially exposed.
Frequently Asked Questions
65,535 per transport protocol (TCP and UDP). Ports 0 to 1023 are 'well-known ports' assigned to common services. 1024 to 49151 are 'registered ports' for applications. 49152 to 65535 are 'dynamic/ephemeral ports' used temporarily by clients.
Yes. TCP and UDP ports are independent namespaces. Port 53 is used by DNS for both TCP and UDP, for example. A service listening on TCP port 80 and a different service listening on UDP port 80 would not conflict.
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