Common Port Numbers Reference
Search any port number or service · see what normally runs there and whether it belongs on the public internet.
Frequently asked
Which ports should never be publicly exposed?
Databases (5432 Postgres, 3306 MySQL, 27017 MongoDB, 6379 Redis), remote admin (3389 RDP, 23 Telnet), and file shares (445 SMB). Shodan indexes them within hours of exposure · put them behind a VPN or private network.
Is running SSH on a non-standard port real security?
It cuts log noise from automated scans, nothing more · scanners find it anyway. Real SSH hardening is key-only auth, no root login, and fail2ban or a VPN. Obscurity is seasoning, not a meal.
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