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.

تقرير النطاق google.com:80

Info Ping HTTP TCP UDP MTR DNS

فحص TCP google.com:80

تم الفحص بتوقيت Apr 23, 2026 19:00:15 UTC |

| إعادة الفحص |

الموقع	النتيجة	الوقت	عنوان IP
Albania, Tirana	Connected	99.0 ms	172.217.22.238
Australia, Sydney	Connected	0.0 ms	172.217.25.174
Bosnia and Herzegovina, Novi Travnik	Connected	48.0 ms	142.251.140.78
Bulgaria, Sofia	Connected	2.0 ms	192.178.25.238
Canada, Montreal	Connected	2.0 ms	64.233.178.101
Switzerland, Bern	Connected	3.0 ms	74.125.29.101
Chile, Santiago	Connected	0.0 ms	142.250.0.138
China, Hohhot	ERROR	-	108.177.98.138
Germany, Nuernberg	Connected	4.0 ms	142.251.20.113
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.20.102
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.110.102
Germany, Limburg	Connected	2.0 ms	142.251.13.139
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.13.139
Germany, Duesseldorf	Connected	7.0 ms	142.251.168.138
Denmark, Glostrup Municipality	Connected	12.0 ms	192.178.25.14
Spain, Bilbao	Connected	37.0 ms	142.251.13.138
Finland, Helsinki	Connected	39.0 ms	192.178.25.78
Finland, Helsinki	Connected	8.0 ms	142.251.143.142
France, Paris	Connected	9.0 ms	172.217.22.14
United Kingdom, London	Connected	6.0 ms	142.250.140.101
Georgia, Tbilisi	ERROR	-	google.com
Greece, Athens	ERROR	-	google.com
Hong Kong, Hong Kong	Connected	4.0 ms	216.58.198.14
Croatia, Zagreb	Connected	24.0 ms	142.251.110.138
Hungary, Budapest	Connected	15.0 ms	172.217.171.174
Indonesia, Jakarta	Connected	0.0 ms	74.125.130.100
Israel, Petach Tikwa	Connected	2.0 ms	142.250.75.46
Israel, Netanja	Connected	2.0 ms	142.250.75.78
India, New Delhi	Connected	1.0 ms	142.250.192.206
Iceland, Reykjavik (Miðborg)	Connected	36.0 ms	172.217.23.238
Italy, Como	Connected	11.0 ms	142.251.141.238
Kuwait, Kuwait City	ERROR	-	google.com
Lithuania, Pilaite	Connected	52.0 ms	172.217.19.238
Latvia, Riga	Connected	31.0 ms	142.250.102.138
Moldova, Chisinau	Connected	125.0 ms	192.178.24.174
Netherlands, Amsterdam	Connected	2.0 ms	142.251.142.206
Netherlands, Amsterdam	Connected	2.0 ms	172.217.23.238
Netherlands, Amsterdam	Connected	1.0 ms	172.217.23.238
Netherlands, Amsterdam	Connected	1.0 ms	142.251.142.206
Norway, Oslo	Connected	42.0 ms	209.85.203.113
Poland, Warsaw	ERROR	-	-
Romania, Bacău	Connected	38.0 ms	142.251.20.100
Romania, Bucharest	Connected	8.0 ms	192.178.24.14
Serbia, Belgrade	ERROR	-	-
Singapore, Singapore	Connected	1.0 ms	142.251.12.100
Turkey, Istanbul	Connected	10.0 ms	172.217.22.238
Taiwan, Taipei	Connected	1.0 ms	142.250.198.78
United States, Miami	Connected	1.0 ms	142.251.214.174
United States, Dallas	Connected	19.0 ms	142.251.116.139
United States, Kansas City	Connected	28.0 ms	209.85.145.138
United States, Dallas	Connected	1.0 ms	173.194.208.102
South Africa, Johannesburg	Connected	0.0 ms	192.178.54.46