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.

ऑनलाइन TCP पोर्ट तपासणी — 50+ ठिकाणांहून कनेक्टिव्हिटी चाचणी

Name: Check-Host TCP Port Connectivity Test
Author: Check-Host

प्रगत सेटिंग्ज

जागतिक नकाशा दाखवा

Info Ping HTTP TCP UDP MTR DNS

Check TCP Port Availability

Domain किंवा IP आणि port टाका (उदा. 1.1.1.1:80).

उदाहरणे: 1.1.1.1:80 check-host.cc:443 8.8.8.8:53

सामान्य TCP Ports

Network monitoring मधील वारंवार वापरले जाणारे ports.

Port	सेवा	वर्णन
20	FTP Data	FTP data transfer.
21	FTP Control	FTP commands.
22	SSH	SSH secure access.
23	Telnet	Telnet (जुना).
25	SMTP	SMTP email.
53	DNS	DNS/TCP.
80	HTTP	HTTP.
110	POP3	POP3.
143	IMAP	IMAP.
443	HTTPS	HTTPS.
445	SMB/CIFS	SMB.
465	SMTPS	Secure SMTP.
587	SMTP Submission	Mail submission.
993	IMAPS	IMAP/SSL.
995	POP3S	POP3/SSL.
1433	MSSQL	MS SQL Server.
3306	MySQL	MySQL.
3389	RDP	RDP.
5432	PostgreSQL	PostgreSQL.
8080	HTTP Alternate	Proxy/dev server.

Global TCP Port Checker

50+ ठिकाणांवरून 3-way TCP handshake द्वारे port open/closed/blocked तपासतो.

Firewall & Routing Validation

Local test यशस्वी पण global TCP अयशस्वी = geoblocking किंवा चुकीचे firewall configuration.

Application vs. Transport Layer

Layer 4 test — databases, mail servers, SSH credentials शिवाय तपासता येते.

Handshake Latency Analysis

TCP handshake round-trip वेळ मोजतो. Live TCP mode real-time monitoring करते.