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.

Bericht für 1.1.1.1:80

Info Ping HTTP TCP UDP MTR DNS

TCP prüfen 1.1.1.1:80

Geprüft am Jun 13, 2026 12:33:05 UTC |

| Erneut prüfen |

Standort	Ergebnis	Zeit	IP-Adresse
Albania, Tirana	Connected	32.0 ms	1.1.1.1
Australia, Sydney	Connected	1.0 ms	1.1.1.1
Bosnia and Herzegovina, Novi Travnik	Connected	15.0 ms	1.1.1.1
Bulgaria, Sofia	Connected	0.0 ms	1.1.1.1
Canada, Montreal	Connected	8.0 ms	1.1.1.1
Switzerland, Bern	Connected	5.0 ms	1.1.1.1
Switzerland, Zurich	Connected	2.0 ms	1.1.1.1
Chile, Santiago	Connected	2.0 ms	1.1.1.1
China, Hohhot	Connected	197.0 ms	1.1.1.1
Germany, Nuernberg	Connected	14.0 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, Limburg	Connected	1.0 ms	1.1.1.1
Germany, Frankfurt am Main	Connected	1.0 ms	1.1.1.1
Germany, Duesseldorf	Connected	1.0 ms	1.1.1.1
Germany, Frankfurt am Main	Connected	1.0 ms	1.1.1.1
Denmark, Glostrup Municipality	Connected	13.0 ms	1.1.1.1
Spain, Barcelona	Connected	24.0 ms	1.1.1.1
Finland, Helsinki	Connected	9.0 ms	1.1.1.1
Finland, Helsinki	Connected	34.0 ms	1.1.1.1
France, Gravelines	Connected	5.0 ms	1.1.1.1
France, Paris	Connected	10.0 ms	1.1.1.1
United Kingdom, London	Connected	6.0 ms	1.1.1.1
Georgia, Tbilisi	Connected	275.0 ms	1.1.1.1
Croatia, Zagreb	Connected	28.0 ms	1.1.1.1
Hungary, Budapest	Connected	15.0 ms	1.1.1.1
Indonesia, Jakarta	Connected	1.0 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
India, New Delhi	Connected	1.0 ms	1.1.1.1
Iceland, Reykjavik (Miðborg)	Connected	2.0 ms	1.1.1.1
Italy, Como	Connected	1.0 ms	1.1.1.1
Kazakhstan, Almaty	Connected	25.0 ms	1.1.1.1
Lithuania, Pilaite	Connected	31.0 ms	1.1.1.1
Latvia, Riga	Connected	32.0 ms	1.1.1.1
Moldova, Chisinau	Connected	34.0 ms	1.1.1.1
Netherlands, Amsterdam	Connected	1.0 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	22.0 ms	1.1.1.1
Romania, Bacău	Connected	39.0 ms	1.1.1.1
Romania, Bucharest	Connected	8.0 ms	1.1.1.1
Serbia, Belgrade	Connected	6.0 ms	1.1.1.1
Russia, Moscow	Connected	23.0 ms	1.1.1.1
Saudi Arabia, Riyadh	Connected	14.0 ms	1.1.1.1
Tor, Onion	Connected	54.0 ms	1.1.1.1
Tor, Onion	Connected	86.0 ms	1.1.1.1
Tor, Onion	Connected	105.0 ms	1.1.1.1
Turkey, Istanbul	Connected	2.0 ms	1.1.1.1
Turkey, Istanbul	Connected	2.0 ms	1.1.1.1
Taiwan, Taipei	Connected	1.0 ms	1.1.1.1
Ukraine, Khmelnytskyi	Connected	12.0 ms	1.1.1.1
United States, Dallas	Connected	16.0 ms	1.1.1.1
United States, Kansas City	Connected	4.0 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	8.0 ms	1.1.1.1
United States, Miami	Connected	1.0 ms	1.1.1.1
South Africa, Johannesburg	Connected	1.0 ms	1.1.1.1