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 50+ 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.

Report for ru-stp-baxet.check-host.eu:80

Name: Check-Host ru-stp-baxet.check-host.eu:80 Test łączności TCP
Author: Check-Host

Info Ping HTTP TCP UDP MTR DNS

Check TCP ru-stp-baxet.check-host.eu:80

Checked Apr 20, 2026 20:21:30 UTC |

| Check again |

Location	Result	Time	IP Address
Albania, Tirana	Connected	88.0 ms	194.87.69.212
Australia, Sydney	Connected	282.0 ms	194.87.69.212
Bosnia and Herzegovina, Novi Travnik	Connected	55.0 ms	194.87.69.212
Bulgaria, Sofia	Connected	69.0 ms	194.87.69.212
Canada, Montreal	Connected	126.0 ms	194.87.69.212
Switzerland, Bern	Connected	36.0 ms	194.87.69.212
Chile, Santiago	Connected	222.0 ms	194.87.69.212
China, Hohhot	Connected	290.0 ms	194.87.69.212
Germany, Nuernberg	Connected	34.0 ms	194.87.69.212
Germany, Frankfurt am Main	Connected	38.0 ms	194.87.69.212
Germany, Frankfurt am Main	Connected	30.0 ms	194.87.69.212
Germany, Limburg	Connected	30.0 ms	194.87.69.212
Germany, Frankfurt am Main	Connected	30.0 ms	194.87.69.212
Germany, Duesseldorf	Connected	34.0 ms	194.87.69.212
Denmark, Glostrup Municipality	Connected	12.0 ms	194.87.69.212
Spain, Bilbao	Connected	78.0 ms	194.87.69.212
Finland, Helsinki	ERROR	-	194.87.69.212
Finland, Helsinki	Connected	18.0 ms	194.87.69.212
France, Gravelines	Connected	39.0 ms	194.87.69.212
France, Paris	Connected	9.0 ms	194.87.69.212
United Kingdom, London	Connected	42.0 ms	194.87.69.212
Georgia, Tbilisi	ERROR	-	ru-stp-baxet.check-host.eu
Greece, Athens	ERROR	-	ru-stp-baxet.check-host.eu
Hong Kong, Hong Kong	Connected	36.0 ms	194.87.69.212
Croatia, Zagreb	Connected	59.0 ms	194.87.69.212
Hungary, Budapest	Connected	15.0 ms	194.87.69.212
Indonesia, Jakarta	Connected	332.0 ms	194.87.69.212
Israel, Petach Tikwa	Connected	88.0 ms	194.87.69.212
Israel, Netanja	Connected	99.0 ms	194.87.69.212
India, New Delhi	Connected	387.0 ms	194.87.69.212
Iceland, Reykjavik (Miðborg)	Connected	74.0 ms	194.87.69.212
Kuwait, Kuwait City	ERROR	-	ru-stp-baxet.check-host.eu
Lithuania, Pilaite	ERROR	-	194.87.69.212
Latvia, Riga	Connected	106.0 ms	194.87.69.212
Moldova, Chisinau	Connected	35.0 ms	194.87.69.212
Netherlands, Amsterdam	Connected	35.0 ms	194.87.69.212
Netherlands, Amsterdam	Connected	35.0 ms	194.87.69.212
Netherlands, Amsterdam	Connected	34.0 ms	194.87.69.212
Netherlands, Amsterdam	Connected	93.0 ms	194.87.69.212
Norway, Oslo	Connected	18.0 ms	194.87.69.212
Poland, Warsaw	Connected	16.0 ms	194.87.69.212
Romania, Bacău	Connected	67.0 ms	194.87.69.212
Romania, Bucharest	Connected	54.0 ms	194.87.69.212
Serbia, Belgrade	Connected	30.0 ms	194.87.69.212
Russia, St Petersburg	Connected	0.0 ms	194.87.69.212
Singapore, Singapore	Connected	278.0 ms	194.87.69.212
Turkey, Istanbul	Connected	70.0 ms	194.87.69.212
Taiwan, Taipei	Connected	293.0 ms	194.87.69.212
United States, Miami	Connected	142.0 ms	194.87.69.212
United States, Dallas	Connected	155.0 ms	194.87.69.212
United States, Kansas City	Connected	147.0 ms	194.87.69.212
United States, Dallas	Connected	158.0 ms	194.87.69.212
South Africa, Johannesburg	Connected	200.0 ms	194.87.69.212