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 golem.de:80

Location	Result	Time	IP Address
Albania, Tirana	Connected	80.0 ms	77.247.84.129
Australia, Sydney	Connected	290.0 ms	77.247.84.129
Bosnia and Herzegovina, Novi Travnik	Connected	30.0 ms	77.247.84.129
Bulgaria, Sofia	Connected	48.0 ms	77.247.84.129
Canada, Montreal	Connected	106.0 ms	77.247.84.129
Switzerland, Bern	Connected	15.0 ms	77.247.84.129
Chile, Santiago	Connected	209.0 ms	77.247.84.129
China, Hohhot	Connected	240.0 ms	77.247.84.129
Germany, Nuernberg	Connected	13.0 ms	77.247.84.129
Germany, Frankfurt am Main	Connected	9.0 ms	77.247.84.129
Germany, Frankfurt am Main	Connected	9.0 ms	77.247.84.129
Germany, Limburg	Connected	10.0 ms	77.247.84.129
Germany, Frankfurt am Main	Connected	9.0 ms	77.247.84.129
Germany, Duesseldorf	Connected	13.0 ms	77.247.84.129
Denmark, Glostrup Municipality	Connected	37.0 ms	77.247.84.129
Spain, Bilbao	Connected	57.0 ms	77.247.84.129
Finland, Helsinki	Connected	67.0 ms	77.247.84.129
Finland, Helsinki	Connected	42.0 ms	77.247.84.129
France, Gravelines	Connected	21.0 ms	77.247.84.129
France, Paris	Connected	59.0 ms	77.247.84.129
United Kingdom, London	Connected	29.0 ms	77.247.84.129
Georgia, Tbilisi	ERROR	-	golem.de
Greece, Athens	ERROR	-	golem.de
Hong Kong, Hong Kong	Connected	16.0 ms	77.247.84.129
Croatia, Zagreb	Connected	27.0 ms	77.247.84.129
Hungary, Budapest	Connected	55.0 ms	77.247.84.129
Indonesia, Jakarta	Connected	253.0 ms	77.247.84.129
Israel, Petach Tikwa	Connected	75.0 ms	77.247.84.129
Israel, Netanja	Connected	68.0 ms	77.247.84.129
India, New Delhi	Connected	264.0 ms	77.247.84.129
Iceland, Reykjavik (Miðborg)	Connected	54.0 ms	77.247.84.129
Italy, Como	Connected	26.0 ms	77.247.84.129
Kuwait, Kuwait City	ERROR	-	golem.de
Lithuania, Pilaite	Connected	163.0 ms	77.247.84.129
Latvia, Riga	Connected	47.0 ms	77.247.84.129
Moldova, Chisinau	Connected	61.0 ms	77.247.84.129
Netherlands, Amsterdam	Connected	13.0 ms	77.247.84.129
Netherlands, Amsterdam	Connected	15.0 ms	77.247.84.129
Netherlands, Amsterdam	Connected	13.0 ms	77.247.84.129
Netherlands, Amsterdam	Connected	13.0 ms	77.247.84.129
Norway, Oslo	Connected	33.0 ms	77.247.84.129
Poland, Warsaw	Connected	22.0 ms	77.247.84.129
Romania, Bacău	Connected	42.0 ms	77.247.84.129
Romania, Bucharest	Connected	32.0 ms	77.247.84.129
Serbia, Belgrade	Connected	52.0 ms	77.247.84.129
Russia, St Petersburg	ERROR	-	77.247.84.129
Singapore, Singapore	Connected	170.0 ms	77.247.84.129
Turkey, Istanbul	Connected	44.0 ms	77.247.84.129
Taiwan, Taipei	Connected	268.0 ms	77.247.84.129
United States, Miami	Connected	128.0 ms	77.247.84.129
United States, Dallas	Connected	135.0 ms	77.247.84.129
United States, Kansas City	Connected	176.0 ms	77.247.84.129
United States, Dallas	Connected	133.0 ms	77.247.84.129
South Africa, Johannesburg	Connected	175.0 ms	77.247.84.129

Albania, Tirana

Connected

80.0 ms

77.247.84.129

Australia, Sydney

Connected

290.0 ms

77.247.84.129

Bosnia and Herzegovina, Novi Travnik

Connected

30.0 ms

77.247.84.129

Bulgaria, Sofia

Connected

48.0 ms

77.247.84.129

Canada, Montreal

Connected

106.0 ms

77.247.84.129

Switzerland, Bern

Connected

15.0 ms

77.247.84.129

Chile, Santiago

Connected

209.0 ms

77.247.84.129

China, Hohhot

Connected

240.0 ms

77.247.84.129

Germany, Nuernberg

Connected

13.0 ms

77.247.84.129

Germany, Frankfurt am Main

Connected

9.0 ms

77.247.84.129

Germany, Frankfurt am Main

Connected

9.0 ms

77.247.84.129

Germany, Limburg

Connected

10.0 ms

77.247.84.129

Germany, Frankfurt am Main

Connected

9.0 ms

77.247.84.129

Germany, Duesseldorf

Connected

13.0 ms

77.247.84.129

Denmark, Glostrup Municipality

Connected

37.0 ms

77.247.84.129

Spain, Bilbao

Connected

57.0 ms

77.247.84.129

Finland, Helsinki

Connected

67.0 ms

77.247.84.129

Finland, Helsinki

Connected

42.0 ms

77.247.84.129

France, Gravelines

Connected

21.0 ms

77.247.84.129

France, Paris

Connected

59.0 ms

77.247.84.129

United Kingdom, London

Connected

29.0 ms

77.247.84.129

Georgia, Tbilisi

ERROR

-

golem.de

Greece, Athens

ERROR

-

golem.de

Hong Kong, Hong Kong

Connected

16.0 ms

77.247.84.129

Croatia, Zagreb

Connected

27.0 ms

77.247.84.129

Hungary, Budapest

Connected

55.0 ms

77.247.84.129

Indonesia, Jakarta

Connected

253.0 ms

77.247.84.129

Israel, Petach Tikwa

Connected

75.0 ms

77.247.84.129

Israel, Netanja

Connected

68.0 ms

77.247.84.129

India, New Delhi

Connected

264.0 ms

77.247.84.129

Iceland, Reykjavik (Miðborg)

Connected

54.0 ms

77.247.84.129

Italy, Como

Connected

26.0 ms

77.247.84.129

Kuwait, Kuwait City

ERROR

-

golem.de

Lithuania, Pilaite

Connected

163.0 ms

77.247.84.129

Latvia, Riga

Connected

47.0 ms

77.247.84.129

Moldova, Chisinau

Connected

61.0 ms

77.247.84.129

Netherlands, Amsterdam

Connected

13.0 ms

77.247.84.129

Netherlands, Amsterdam

Connected

15.0 ms

77.247.84.129

Netherlands, Amsterdam

Connected

13.0 ms

77.247.84.129

Netherlands, Amsterdam

Connected

13.0 ms

77.247.84.129

Norway, Oslo

Connected

33.0 ms

77.247.84.129

Poland, Warsaw

Connected

22.0 ms

77.247.84.129

Romania, Bacău

Connected

42.0 ms

77.247.84.129

Romania, Bucharest

Connected

32.0 ms

77.247.84.129

Serbia, Belgrade

Connected

52.0 ms

77.247.84.129

Russia, St Petersburg

ERROR

-

77.247.84.129

Singapore, Singapore

Connected

170.0 ms

77.247.84.129

Turkey, Istanbul

Connected

44.0 ms

77.247.84.129

Taiwan, Taipei

Connected

268.0 ms

77.247.84.129

United States, Miami

Connected

128.0 ms

77.247.84.129

United States, Dallas

Connected

135.0 ms

77.247.84.129

United States, Kansas City

Connected

176.0 ms

77.247.84.129

United States, Dallas

Connected

133.0 ms

77.247.84.129

South Africa, Johannesburg

Connected

175.0 ms

77.247.84.129

Check-Host.cc

Check TCP golem.de:80