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Common TCP and UDP Port Numbers (Quick Reference)
Published Jun 1, 2026
Common TCP and UDP Port Numbers
Port numbers identify which application or service should receive traffic on a host. Combined with an IP address, they form a socket: 192.168.1.1:443.
Use the Port Number Reference to search by number or service name.
Port ranges
| Range | Name | Notes |
|---|---|---|
| 0–1023 | Well-known | IANA assigned; often need root to bind |
| 1024–49151 | Registered | IANA assigned applications |
| 49152–65535 | Dynamic/private | Ephemeral client ports |
Essential ports every admin should know
| Port | Service | Protocol | Description |
|---|---|---|---|
| 22 | SSH | TCP | Secure remote shell |
| 53 | DNS | TCP/UDP | Domain name resolution |
| 80 | HTTP | TCP | Unencrypted web |
| 443 | HTTPS | TCP/UDP | TLS-encrypted web |
| 25 | SMTP | TCP | Mail delivery |
| 587 | Submission | TCP | Mail client submission |
| 3306 | MySQL | TCP | MySQL / MariaDB |
| 5432 | PostgreSQL | TCP | PostgreSQL database |
| 6379 | Redis | TCP | In-memory cache (unofficial) |
| 8080 | HTTP-alt | TCP | Proxies / dev servers |
TCP vs UDP
- TCP — reliable, ordered delivery (HTTP, SSH, databases)
- UDP — fast, no guarantee (DNS queries, VoIP, gaming, QUIC/HTTP3)
Some services use both: DNS uses UDP for queries and TCP for large zone transfers.
Official vs unofficial
Official ports are registered with IANA. Unofficial ports are community conventions (Redis 6379, MongoDB 27017) — widely used but not formally assigned.
Security tip
Close unused ports at the firewall. Scanning for open ports (nmap) is standard in security audits — know what should be listening before exposing a server.