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.

Rapport pour google.com:80

Info Ping HTTP TCP UDP MTR DNS

Vérifier TCP google.com:80

Vérifié le Oct 23, 2026 07:12:15 UTC |

| Revérifier |

Emplacement	Résultat	Temps	Adresse IP
Australia, Sydney	Connected	0.0 ms	172.217.25.174
Bosnia and Herzegovina, Novi Travnik	Connected	16.0 ms	192.178.24.46
Bulgaria, Sofia	Connected	6.0 ms	172.217.171.78
Canada, Montreal	Connected	9.0 ms	74.125.197.139
Switzerland, Bern	Connected	1.0 ms	142.250.180.14
Switzerland, Zurich	Connected	12.0 ms	142.251.20.138
China, Hohhot	ERROR	-	142.250.73.78
Cyprus, Larnaca	Connected	9.0 ms	142.250.75.78
Germany, Nuernberg	Connected	4.0 ms	142.251.13.139
Germany, Frankfurt am Main	Connected	1.0 ms	142.251.14.101
Germany, Frankfurt am Main	Connected	0.0 ms	142.251.13.138
Germany, Frankfurt am Main	Connected	1.0 ms	142.250.154.139
Germany, Koblenz	Connected	28.0 ms	142.251.20.113
Germany, Frankfurt am Main	Connected	5.0 ms	142.251.13.101
Denmark, Glostrup Municipality	Connected	39.0 ms	216.58.201.206
Spain, Bilbao	Connected	38.0 ms	142.251.13.113
Spain, Barcelona	Connected	22.0 ms	172.217.20.46
Finland, Helsinki	Connected	6.0 ms	64.233.164.138
Finland, Helsinki	Connected	7.0 ms	172.217.20.174
France, Gravelines	Connected	13.0 ms	142.251.14.102
France, Paris	Connected	18.0 ms	172.217.22.46
United Kingdom, London	Connected	7.0 ms	142.251.29.113
Hong Kong, Hong Kong	Connected	1.0 ms	172.217.23.238
Croatia, Zagreb	Connected	24.0 ms	142.251.20.102
Hungary, Budapest	Connected	90.0 ms	142.251.14.139
Israel, Petach Tikwa	Connected	2.0 ms	142.250.75.46
Israel, Netanja	Connected	2.0 ms	142.250.75.110
Iran, Tehran	Connected	76.0 ms	216.239.38.120
Iran, Tehran	Connected	77.0 ms	216.239.38.120
Iceland, Reykjavik (Miðborg)	Connected	23.0 ms	172.253.116.101
Italy, Como	Connected	1.0 ms	192.178.194.113
Japan, Tokyo	Connected	3.0 ms	192.178.226.139
South Korea, Seoul	Connected	37.0 ms	142.251.118.139
Kazakhstan, Almaty	ERROR	-	-
Lithuania, Pilaite	Connected	104.0 ms	142.251.98.101
Latvia, Riga	Connected	99.0 ms	192.178.183.138
Netherlands, Amsterdam	Connected	1.0 ms	142.251.39.142
Netherlands, Amsterdam	Connected	3.0 ms	192.178.24.142
Netherlands, Amsterdam	Connected	1.0 ms	192.178.24.142
Netherlands, Amsterdam	Connected	1.0 ms	142.251.142.206
Netherlands, Eygelshoven	Connected	4.0 ms	142.251.39.142
Norway, Oslo	Connected	39.0 ms	142.250.178.46
Poland, Warsaw	Connected	16.0 ms	142.251.98.100
Romania, Bacău	Connected	39.0 ms	142.251.13.113
Romania, Bucharest	Connected	8.0 ms	142.251.142.110
Serbia, Belgrade	Connected	13.0 ms	192.178.24.78
Russia, Moscow	Connected	26.0 ms	64.233.162.102
Singapore, Singapore	Connected	33.0 ms	74.125.24.138
Tor, Onion	Connected	166.0 ms	google.com
Tor, Onion	Connected	674.0 ms	google.com
Tor, Onion	Connected	36.0 ms	google.com
Turkey, Istanbul	Connected	30.0 ms	192.178.194.101
Ukraine, Khmelnytskyi	Connected	15.0 ms	142.250.130.113
United States, Dallas	Connected	1.0 ms	142.250.26.102
United States, Los Angeles	Connected	29.0 ms	142.251.210.142
United States, Houston	Connected	7.0 ms	173.194.208.138
United States, Miami	Connected	1.0 ms	142.251.215.46
South Africa, Johannesburg	Connected	3.0 ms	142.251.47.206