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.

check-host.cc:80 için Rapor

Name: Check-Host check-host.cc:80 TCP Port Bağlantı Testi
Author: Check-Host

Info Ping HTTP TCP UDP MTR DNS

TCP Kontrol check-host.cc:80

Oct 24, 2026 20:46:13 UTC tarihinde kontrol edildi |

| Tekrar kontrol et |

Konum	Sonuç	Süre	IP Adresi
Albania, Tirana	ERROR	-	34.36.183.77
Australia, Sydney	Connected	1.0 ms	34.36.183.77
Bosnia and Herzegovina, Novi Travnik	Connected	34.0 ms	34.36.183.77
Bulgaria, Sofia	Connected	22.0 ms	34.36.183.77
Canada, Montreal	Connected	2.0 ms	34.36.183.77
Switzerland, Bern	Connected	4.0 ms	34.36.183.77
Switzerland, Zurich	Connected	21.0 ms	34.36.183.77
China, Hohhot	Connected	137.0 ms	34.36.183.77
Cyprus, Larnaca	Connected	41.0 ms	34.36.183.77
Germany, Nuernberg	Connected	5.0 ms	34.36.183.77
Germany, Frankfurt am Main	Connected	0.0 ms	34.36.183.77
Germany, Frankfurt am Main	Connected	0.0 ms	34.36.183.77
Germany, Frankfurt am Main	Connected	1.0 ms	34.36.183.77
Germany, Koblenz	Connected	20.0 ms	34.36.183.77
Germany, Frankfurt am Main	Connected	5.0 ms	34.36.183.77
Denmark, Glostrup Municipality	Connected	29.0 ms	34.36.183.77
Spain, Bilbao	Connected	38.0 ms	34.36.183.77
Spain, Barcelona	Connected	21.0 ms	34.36.183.77
Finland, Helsinki	Connected	7.0 ms	34.36.183.77
Finland, Helsinki	Connected	12.0 ms	34.36.183.77
France, Gravelines	Connected	5.0 ms	34.36.183.77
France, Paris	Connected	37.0 ms	34.36.183.77
United Kingdom, London	Connected	8.0 ms	34.36.183.77
Hong Kong, Hong Kong	Connected	6.0 ms	34.36.183.77
Croatia, Zagreb	Connected	29.0 ms	34.36.183.77
Hungary, Budapest	Connected	125.0 ms	34.36.183.77
Israel, Petach Tikwa	Connected	2.0 ms	34.36.183.77
Israel, Netanja	Connected	3.0 ms	34.36.183.77
Iran, Tehran	Connected	73.0 ms	34.36.183.77
Iran, Tehran	Connected	128.0 ms	34.36.183.77
Iceland, Reykjavik (Miðborg)	Connected	23.0 ms	34.36.183.77
Italy, Como	Connected	1.0 ms	34.36.183.77
Japan, Tokyo	Connected	1.0 ms	34.36.183.77
South Korea, Seoul	Connected	34.0 ms	34.36.183.77
Kazakhstan, Almaty	Connected	90.0 ms	34.36.183.77
Lithuania, Pilaite	Connected	103.0 ms	34.36.183.77
Latvia, Riga	Connected	271.0 ms	34.36.183.77
Moldova, Chisinau	Connected	218.0 ms	34.36.183.77
Netherlands, Amsterdam	Connected	5.0 ms	34.36.183.77
Netherlands, Amsterdam	Connected	6.0 ms	34.36.183.77
Netherlands, Amsterdam	Connected	6.0 ms	34.36.183.77
Netherlands, Amsterdam	Connected	5.0 ms	34.36.183.77
Netherlands, Eygelshoven	Connected	51.0 ms	34.36.183.77
Norway, Oslo	Connected	12.0 ms	34.36.183.77
Poland, Warsaw	Connected	16.0 ms	34.36.183.77
Romania, Bacău	Connected	53.0 ms	34.36.183.77
Romania, Bucharest	Connected	32.0 ms	34.36.183.77
Serbia, Belgrade	Connected	34.0 ms	34.36.183.77
Russia, Moscow	Connected	29.0 ms	34.36.183.77
Singapore, Singapore	Connected	1.0 ms	34.36.183.77
Tor, Onion	Connected	129.0 ms	check-host.cc
Tor, Onion	Connected	346.0 ms	check-host.cc
Tor, Onion	Connected	132.0 ms	check-host.cc
Turkey, Istanbul	Connected	29.0 ms	34.36.183.77
Ukraine, Khmelnytskyi	Connected	31.0 ms	34.36.183.77
United States, Dallas	Connected	1.0 ms	34.36.183.77
United States, Los Angeles	Connected	42.0 ms	34.36.183.77
United States, Houston	Connected	7.0 ms	34.36.183.77
United States, Miami	Connected	28.0 ms	34.36.183.77
South Africa, Johannesburg	Connected	2.0 ms	34.36.183.77