Only expose what you need
If a port is open publicly, treat it as internet-facing. Restrict by IP where possible.
TCP
Exposure
Range scan
Port checker
Check whether a port is reachable from the public internet. Useful for validating firewall rules, NAT, and service exposure after deployments or migrations.
Single port
Fast check for a known service
Ranges
Validate groups (e.g. 80/443/22)
Signal
Clear “open/closed/filtered” style output
Check an IP
Enter an IP address and one port (or a simple comma-separated list).
Results
Live open vs closed port results.
Run a port check to see live results here.
Guidance
How to interpret open/closed results safely.
Consider NAT and firewalls
A closed result can be a firewall rule, a missing NAT mapping, or a service not listening.
Verify locally too
Check from within the network to isolate whether the issue is exposure or the service itself.
FAQ
Quick answers to common questions.
What does “filtered” mean?
It usually indicates a firewall silently dropping packets rather than actively rejecting the connection.
Why does it show open but I still can’t log in?
Open only means reachable. Auth, TLS, host-based firewalls, or app errors can still prevent use.
Tools
Need help securing your exposure?
We can lock down open ports, implement secure access patterns, and keep your services reachable only where they should be.
Least privilege. Clear rules. Verified access.
Networking
Security
Access control