Common Ports Reference
Common TCP/UDP port reference: well-known (0-1023) ports mapped to common services (SSH, HTTP, HTTPS, databases …) with short descriptions.
| Port | Service | Note |
|---|---|---|
| 20/21 | FTP | File transfer (21 control, 20 data) |
| 22 | SSH | Secure remote login / SCP / SFTP |
| 23 | Telnet | Plaintext remote terminal (insecure) |
| 25 | SMTP | Mail sending |
| 53 | DNS | Domain name resolution |
| 67/68 | DHCP | Dynamic host configuration |
| 69 | TFTP | Trivial file transfer |
| 80 | HTTP | Hypertext transfer (plaintext) |
| 110 | POP3 | Mail retrieval (POP3) |
| 111 | RPC | Remote procedure call |
| 123 | NTP | Network time sync |
| 135 | MS-RPC | Windows RPC |
| 137-139 | NetBIOS | Windows file/print sharing (NetBIOS) |
| 143 | IMAP | Mail retrieval with folders (IMAP) |
| 161/162 | SNMP | Network management (SNMP) |
| 179 | BGP | Border gateway routing (BGP) |
| 194 | IRC | Internet relay chat |
| 389 | LDAP | Lightweight directory access (LDAP) |
| 443 | HTTPS | Encrypted hypertext transfer (TLS) |
| 465 | SMTPS | Encrypted mail sending (SMTPS) |
| 514 | Syslog | System logging (Syslog) |
| 587 | SMTP Submission | Mail submission (encrypted) |
| 636 | LDAPS | Encrypted directory access (LDAPS) |
| 993 | IMAPS | Encrypted mail retrieval (IMAPS) |
| 995 | POP3S | Encrypted mail retrieval (POP3S) |
| 1433 | MSSQL | SQL Server database |
| 1521 | Oracle | Oracle database |
| 2049 | NFS | Network file system (NFS) |
| 3306 | MySQL | MySQL database |
| 3389 | RDP | Windows remote desktop (RDP) |
| 5432 | PostgreSQL | PostgreSQL database |
| 5672 | RabbitMQ | Message queue (RabbitMQ) |
| 6379 | Redis | In-memory key-value store (Redis) |
| 8080 | HTTP-Alt | Common HTTP alternative (dev) |
| 8443 | HTTPS-Alt | Common HTTPS alternative (dev) |
| 9092 | Kafka | Distributed event stream (Kafka) |
| 9200 | Elasticsearch | Search/analytics engine (Elasticsearch) |
| 11211 | Memcached | Memory cache (Memcached) |
| 27017 | MongoDB | Document database (MongoDB) |
Frequently Asked Questions
Why are 0-1023 called "well-known ports"?
IANA reserves 0-1023 for system/well-known services. They usually require root (or admin) to bind, used by HTTP, SSH, DNS and other standard services.
How are port ranges divided?
0-1023 well-known (system reserved); 1024-49151 registered (user programs register with IANA); 49152-65535 dynamic/private (ephemeral allocation).
How do I see listening ports on my machine?
On Linux use `ss -tlnp` or `netstat -tlnp`; on macOS `lsof -i -P`; on Windows `netstat -ano`.
Why do dev environments prefer 8080 / 8443?
80/443 are often occupied and need admin to bind; 8080/8443 avoid conflicts and need no privilege, so frameworks and local servers default to them.