Infrastructure
Port Checker
Check whether a common TCP service port is reachable on a public hostname.
How to use this tool
Enter a public hostname and a supported service port. The checker attempts a direct connection and reports whether the service is reachable.
Related tool: DNS Record Finder →When to use the Port Checker
Use it to test whether a service is reachable from the internet, for example after opening a firewall rule or when a client cannot connect.
Examples
- Check port 443 on a web server after configuring TLS.
- Confirm SSH on port 22 is closed to the public when it should be.
Common mistakes
- Testing from inside the same network and assuming it is reachable externally.
- Forgetting the cloud security group when the host firewall is already open.
Created by Muhammad Irfan Aslam, Senior Systems & Cloud Engineer.
Case study: AWS infrastructure architecture →Tutorial on LearnWithIrfan: UFW firewall guide →