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Port Checker
Test whether a TCP port on a public hostname or IP address accepts a connection and review connection timing and resolved destination.
What Port Checker does
Port Checker tests TCP connectivity to a selected port on a public hostname or IP address. The report distinguishes an accepted connection from a refusal or timeout and shows the resolved destination and connection timing.
The result is designed for practical network troubleshooting. Trexmi performs the check from its server environment, validates the destination, and presents the important details in a visual report. Network results can vary by resolver, routing, firewall policy, hosting provider, and the configuration of the remote system.
How to use
- Enter a public hostname or IP address.
- Choose a TCP port from 1 to 65535.
- Set the connection timeout.
- Select Check TCP Port.
- Review the connection state, destination, timing, and Raw JSON.
Why use Port Checker?
Focused controls, predictable output, and a workflow designed around this exact transformation.
Clear network result
Get a readable visual result instead of interpreting raw command-line output.
Public targets only
Private, reserved, and internal network destinations are rejected by the server-side checks.
Raw data included
Open Raw JSON when you need structured details for troubleshooting or documentation.
Timing included
See how long the server-side network operation took for useful diagnostic context.
Questions about Port Checker
Practical details about input, output, privacy, limits, and the best way to use this tool.
01 What does an open port mean?
It means the remote destination accepted a TCP connection on that port from the Trexmi server at the time of the test.
02 Does an open port prove the application is working?
No. A TCP handshake only confirms connectivity. Application health, authentication, TLS, and protocol behavior require additional checks.
03 What does a timeout mean?
The checker did not receive a conclusive connection result before the configured timeout. A firewall may be silently dropping traffic.
04 Why can a port be open for me but closed here?
Firewall and routing policies can differ by source network, so reachability from the Trexmi server can differ from reachability from your device.
05 Can I check private IP addresses?
No. Private, reserved, loopback, and internal destinations are blocked; the tool is limited to public network targets.
How Port Checker works
Port Checker resolves a public hostname or accepts a public IP address, validates that the destination is not private or reserved, and attempts a TCP connection to the selected port. A successful connection means the destination accepted the TCP handshake from the Trexmi server at that moment.
TCP ports are numeric endpoints from 1 through 65535. Common conventions associate ports such as 22 with SSH, 80 with HTTP, and 443 with HTTPS, but a port number alone does not guarantee which application is actually listening. Trexmi therefore labels the common service only as a service hint.
Open, closed, refused, and timed out
An open result means a TCP connection was accepted. A closed or refused result normally means the destination was reachable but did not accept a connection on that port. A timeout means the checker did not receive a conclusive response before the configured limit. Firewalls often drop packets silently, so a timeout does not prove that a host is offline.
Network path differences matter. A port can be reachable from one source network and blocked from another because of firewall rules, access control lists, routing, provider policy, or temporary network conditions.
Public destinations only
Port Checker rejects private, loopback, link-local, and reserved destinations. Hostnames are resolved and checked before the connection attempt. This restriction keeps the feature focused on public services and prevents it from being used as a browser-facing path into internal network resources.
The underlying concepts are standardized by the Internet protocol suite. See RFC 9293 for TCP and the IANA service name and port registry for authoritative references.
How to interpret a port check
A successful TCP handshake does not authenticate the service, prove that an application is healthy, or verify encryption. For example, port 443 may accept TCP while the TLS certificate is invalid or the HTTP application returns an error. Combine the result with protocol-specific checks when diagnosing a real service.
Use SSL Certificate Checker for TLS identity, HTTP Status Checker for web responses, and DNS Lookup to inspect the records that lead to the destination.
Port Checker summary
Port Checker answers one practical question: can the Trexmi server establish a TCP connection to this public host and port now? The visual report combines open, closed, or timeout status with the resolved IP address, service hint, connection timing, and raw structured data for further troubleshooting.