How do I check if a TCP port is open online?

Enter your server's IP address or domain followed by a colon and the port number (e.g. 1.1.1.1:80 or example.com:443) and run a TCP check. The tool attempts a TCP handshake from 65+ global nodes and reports whether each connection succeeded, was refused, or timed out.

What is the difference between a port being refused versus timing out?

A refused connection (TCP RST) means the port is actively closed — the server replied to reject the connection. A timeout means no reply was received at all, which typically indicates a firewall is silently dropping packets before they reach the server or application.

Which TCP ports can I test?

Any valid TCP port from 1 to 65535. Common examples include port 80 (HTTP), 443 (HTTPS), 22 (SSH), 25 (SMTP), 3306 (MySQL), 5432 (PostgreSQL), and 3389 (RDP). No login or special permissions required — the check only verifies whether the TCP handshake completes.

My port is open locally but fails from external nodes — why?

If a port works locally but fails from external nodes, something between the internet and your server is blocking it — commonly a cloud security group, iptables rule, upstream ISP filter, or geoblocking policy. Running the check from multiple regions helps identify whether the block is global or specific to certain countries or ASNs.

Rapport pour 1.1.1.1:80

Info Ping HTTP TCP UDP MTR DNS

Vérifier TCP 1.1.1.1:80

Vérifié le Oct 23, 2026 15:18:29 UTC |

| Revérifier |

Emplacement	Résultat	Temps	Adresse IP
Albania, Tirana	Connected	132.0 ms	1.1.1.1
Australia, Sydney	Connected	4.0 ms	1.1.1.1
Bosnia and Herzegovina, Novi Travnik	Connected	19.0 ms	1.1.1.1
Bulgaria, Sofia	Connected	31.0 ms	1.1.1.1
Canada, Montreal	Connected	8.0 ms	1.1.1.1
Switzerland, Bern	Connected	2.0 ms	1.1.1.1
Switzerland, Zurich	Connected	19.0 ms	1.1.1.1
China, Hohhot	Connected	324.0 ms	1.1.1.1
Cyprus, Larnaca	Connected	2.0 ms	1.1.1.1
Germany, Nuernberg	Connected	16.0 ms	1.1.1.1
Germany, Frankfurt am Main	Connected	0.0 ms	1.1.1.1
Germany, Frankfurt am Main	Connected	1.0 ms	1.1.1.1
Germany, Frankfurt am Main	Connected	1.0 ms	1.1.1.1
Germany, Koblenz	Connected	21.0 ms	1.1.1.1
Germany, Frankfurt am Main	Connected	5.0 ms	1.1.1.1
Denmark, Glostrup Municipality	Connected	80.0 ms	1.1.1.1
Spain, Bilbao	Connected	42.0 ms	1.1.1.1
Spain, Barcelona	Connected	18.0 ms	1.1.1.1
Finland, Helsinki	Connected	5.0 ms	1.1.1.1
Finland, Helsinki	Connected	19.0 ms	1.1.1.1
France, Gravelines	Connected	6.0 ms	1.1.1.1
France, Paris	Connected	19.0 ms	1.1.1.1
United Kingdom, London	Connected	8.0 ms	1.1.1.1
Hong Kong, Hong Kong	Connected	7.0 ms	1.1.1.1
Croatia, Zagreb	Connected	28.0 ms	1.1.1.1
Hungary, Budapest	Connected	28.0 ms	1.1.1.1
Israel, Petach Tikwa	Connected	1.0 ms	1.1.1.1
Israel, Netanja	Connected	1.0 ms	1.1.1.1
Iran, Tehran	Connected	1.0 ms	1.1.1.1
Iran, Tehran	Connected	1.0 ms	1.1.1.1
Iceland, Reykjavik (Miðborg)	Connected	2.0 ms	1.1.1.1
Italy, Como	Connected	0.0 ms	1.1.1.1
Japan, Tokyo	Connected	1.0 ms	1.1.1.1
South Korea, Seoul	Connected	2.0 ms	1.1.1.1
Kazakhstan, Almaty	Connected	3.0 ms	1.1.1.1
Lithuania, Pilaite	Connected	55.0 ms	1.1.1.1
Latvia, Riga	Connected	62.0 ms	1.1.1.1
Moldova, Chisinau	Connected	71.0 ms	1.1.1.1
Netherlands, Amsterdam	Connected	2.0 ms	1.1.1.1
Netherlands, Amsterdam	Connected	3.0 ms	1.1.1.1
Netherlands, Amsterdam	Connected	1.0 ms	1.1.1.1
Netherlands, Amsterdam	Connected	1.0 ms	1.1.1.1
Netherlands, Eygelshoven	Connected	4.0 ms	1.1.1.1
Norway, Oslo	Connected	0.0 ms	1.1.1.1
Poland, Warsaw	Connected	16.0 ms	1.1.1.1
Romania, Bacău	Connected	52.0 ms	1.1.1.1
Romania, Bucharest	Connected	8.0 ms	1.1.1.1
Serbia, Belgrade	Connected	7.0 ms	1.1.1.1
Russia, Moscow	Connected	23.0 ms	1.1.1.1
Singapore, Singapore	Connected	3.0 ms	1.1.1.1
Tor, Onion	Connected	289.0 ms	1.1.1.1
Tor, Onion	Connected	134.0 ms	1.1.1.1
Tor, Onion	Connected	405.0 ms	1.1.1.1
Turkey, Istanbul	Connected	10.0 ms	1.1.1.1
Ukraine, Khmelnytskyi	Connected	8.0 ms	1.1.1.1
United States, Dallas	Connected	1.0 ms	1.1.1.1
United States, Los Angeles	Connected	1.0 ms	1.1.1.1
United States, Houston	Connected	7.0 ms	1.1.1.1
United States, Miami	Connected	1.0 ms	1.1.1.1
South Africa, Johannesburg	Connected	2.0 ms	1.1.1.1