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 21, 2026 19:44:19 UTC |

| إعادة الفحص |

الموقع	النتيجة	الوقت	عنوان IP
Albania, Tirana	Connected	49.0 ms	192.178.24.174
Australia, Sydney	Connected	0.0 ms	142.250.183.46
Bosnia and Herzegovina, Novi Travnik	Connected	50.0 ms	142.251.140.78
Bulgaria, Sofia	Connected	0.0 ms	192.178.24.78
Canada, Montreal	Connected	2.0 ms	64.233.178.101
Switzerland, Bern	Connected	3.0 ms	74.125.29.113
Chile, Santiago	Connected	1.0 ms	108.177.123.139
China, Hohhot	ERROR	-	142.250.73.142
Germany, Nuernberg	Connected	4.0 ms	142.251.14.139
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.208.174
Germany, Frankfurt am Main	Connected	0.0 ms	172.217.16.174
Germany, Limburg	Connected	2.0 ms	142.251.110.138
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.13.100
Germany, Duesseldorf	Connected	3.0 ms	142.251.39.142
Denmark, Glostrup Municipality	Connected	12.0 ms	192.178.25.14
Spain, Bilbao	Connected	37.0 ms	142.251.13.139
Finland, Helsinki	Connected	12.0 ms	216.58.198.174
Finland, Helsinki	Connected	16.0 ms	142.251.38.78
France, Gravelines	Connected	11.0 ms	142.251.14.113
France, Paris	Connected	9.0 ms	142.251.39.110
United Kingdom, London	Connected	6.0 ms	142.250.129.100
Georgia, Tbilisi	ERROR	-	google.com
Greece, Athens	ERROR	-	google.com
Hong Kong, Hong Kong	Connected	3.0 ms	216.58.198.14
Croatia, Zagreb	Connected	25.0 ms	142.251.20.113
Hungary, Budapest	Connected	15.0 ms	172.217.171.174
Indonesia, Jakarta	Connected	1.0 ms	172.253.134.139
Israel, Petach Tikwa	Connected	1.0 ms	142.250.75.46
Israel, Netanja	Connected	3.0 ms	142.250.75.46
India, New Delhi	Connected	1.0 ms	142.250.183.206
Iceland, Reykjavik (Miðborg)	Connected	36.0 ms	142.250.180.14
Italy, Como	Connected	24.0 ms	172.217.168.142
Kuwait, Kuwait City	ERROR	-	google.com
Lithuania, Pilaite	Connected	57.0 ms	172.217.19.238
Latvia, Riga	Connected	31.0 ms	142.250.102.139
Moldova, Chisinau	Connected	35.0 ms	192.178.24.174
Netherlands, Amsterdam	Connected	1.0 ms	142.251.142.206
Netherlands, Amsterdam	Connected	3.0 ms	172.217.23.238
Netherlands, Amsterdam	Connected	1.0 ms	172.217.23.238
Netherlands, Amsterdam	Connected	0.0 ms	172.217.23.238
Norway, Oslo	Connected	31.0 ms	209.85.203.101
Poland, Warsaw	Connected	26.0 ms	142.251.98.139
Romania, Bacău	Connected	33.0 ms	192.178.183.113
Romania, Bucharest	Connected	8.0 ms	192.178.24.14
Serbia, Belgrade	Connected	30.0 ms	142.251.20.139
Russia, St Petersburg	Connected	6.0 ms	74.125.131.139
Singapore, Singapore	Connected	0.0 ms	74.125.24.139
Turkey, Istanbul	Connected	10.0 ms	172.217.22.238
Taiwan, Taipei	Connected	1.0 ms	142.250.204.46
United States, Miami	Connected	61.0 ms	142.251.210.78
United States, Dallas	Connected	18.0 ms	142.251.186.102
United States, Kansas City	Connected	32.0 ms	209.85.145.113
United States, Dallas	Connected	2.0 ms	142.251.116.139
South Africa, Johannesburg	Connected	0.0 ms	192.178.54.46