Port Scan
Scan common TCP ports on a host or IP address.
Attempts TCP connections from our server to a curated list of well-known ports
(22, 25, 53, 80, 443, 3306, 5432, 6379, 8080, …) and reports which accept connections.
Useful for verifying that a service you exposed is actually reachable from the public internet,
or for confirming a port you closed is in fact closed. The probe is read-only — we only
check whether the TCP handshake succeeds, never send application data.
Scanning ports...
Reading the result
- Open — the target accepted a TCP connection on that port. Something is listening.
- Closed — the port is reachable at the network level but no service is listening (RST returned).
- Filtered — no response at all; a firewall is silently dropping packets. We can't distinguish "host down" from "firewall" in this state.
Common use cases
- Verify a self-hosted service is exposed — opened port 443 in your firewall? Confirm it's actually reachable from outside.
- Confirm a port closure — after disabling a service, make sure it really stopped listening on the public IP, not just on localhost.
- Spot accidentally exposed admin ports — 22 (SSH), 3389 (RDP), 5432 (Postgres), 6379 (Redis), 9200 (Elasticsearch), and 27017 (MongoDB) should rarely be on the public internet.
- Compare home vs. office vs. mobile — see how restrictive each network's outbound or inbound rules are.
Limitations
- We scan only a small list of common ports. A full 65,535-port scan is intrusive and not what this tool is for; use
nmapfrom a system you own for that. - Some networks deliberately drop probe traffic from cloud IPs. A "filtered" result from us may simply mean our scanning IP is blocked at the target's edge.
- Only scan systems you have permission to scan. Unsolicited scanning of someone else's network may violate their terms of service or local law.