Port Checker

TCP Port Scanner

Initiates TCP handshake from the server side to determine if ports are open. Suitable for origin verification, operations, and environment connectivity troubleshooting.

Check ports online, know immediately if services are reachable.

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Use Cases

When service is just deployed, first test if ports 80, 443, 22, or business ports are actually reachable
Verify if ports are blocked by firewall or security group when troubleshooting connection failures
Verify Web, SSH, database port connectivity and response latency before migration or launch
Check if custom business ports (like 3000, 8080, 3306, 5432) are correctly listening

Features

Open, timeout, or refused at a glance: Less detours in troubleshooting
High-frequency self-check after deployment: Security groups, firewalls, reverse proxies all easy to confirm
Suitable for common services: Web, SSH, databases, gateways, and API service port checks
Clear and intuitive results: Easy one-click connectivity status viewing and continued troubleshooting with DNS, SSL, HTTP tools

How to Use

1.Enter target host (domain or IP) and port list (like 80,443 or 3000-3005)
2.Click check button or use preset host and port combinations for quick testing
3.View scan overview: open port count, total ports, average latency, and timeout error count
4.View each port's status, service name, latency, and details in the result table

FAQ

How to quickly determine if a server port is open?

Enter domain or IP plus port to see if it's reachable, timeout, or refused. Especially suitable for quickly determining if the issue is at network layer or service layer.

Why does port checking fail?

Possible causes include service not started, firewall blocking, security group not allowing, wrong listening address, or network link anomaly. Port checking is the first step in locating such issues.

Is it suitable for troubleshooting Nginx, databases, SSH, and API services?

Yes. Whether 80, 443, 22, or database and custom business ports, connectivity can be judged first.

Does it support multi-port checking?

Suitable for gradually checking open status in multi-port scenarios, convenient for environment acceptance, service launch, and security policy checks.