Network Port Lookup
Type a port number (445, 3389) or a service (rdp, smb, quickbooks, sql) — useful when reading firewall rules, netstat output, or a port-scan report.
Is a port open on your connection?
Check whether a port is reachable on your own public IP, as seen from the internet — the quickest way to confirm a port-forward or firewall rule is actually working. For your safety this only ever tests your own connection (detected automatically) — you can't point it at another address.
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Quick safety notes
- Ports 0–1023 are “well-known” (IANA-assigned), 1024–49151 are registered, 49152–65535 are dynamic/ephemeral — what Windows hands out for outbound connections.
- Seeing a port open on your own PC just means a program is listening —
netstat -abno(admin) shows which one. - Never expose 3389 (RDP), 445 (SMB), or 5900 (VNC) directly to the internet — use a VPN in front.
The lookup runs in your browser; assignments follow the IANA service-name registry plus widely-used vendor defaults. The open-port check runs on our server against your own public IP only — no other address can be entered.