NetOpsKit

Global TCP Port Test

Check whether one public TCP service is reachable from multiple global locations.

Check one TCP port

Only one target and one port are accepted. Presets are conveniences, not recommendations to expose those services publicly.

What does a TCP port test check?

Each Agent attempts a TCP handshake to the selected public target and single port. The test confirms service reachability without sending application credentials or scanning other ports.

Open vs Connection Refused vs Timeout

Open

The TCP handshake succeeded and a service accepted the connection.

Connection Refused

The destination was reachable but actively rejected the connection, often because no service is listening or a firewall sent a rejection.

Timeout

No response arrived before the deadline. Packet filtering, a firewall, routing trouble, or an unreachable destination may cause this. A timeout is not the same as a refused connection.

TCP test vs Ping

Ping uses ICMP and may be filtered independently. TCP tests the actual service port, so it can succeed when Ping is blocked or fail while the host still answers ICMP.

Frequently asked questions

What does a TCP port test check?

It attempts a TCP handshake to one public host and one port from each probe location. It does not scan a port range.

What does Open mean?

Open means the TCP handshake completed and a service accepted the connection on that port.

What does Connection Refused mean?

The target was reachable, but it actively rejected the connection, usually because no service is listening or a firewall rejected it.

What does Timeout mean?

No connection response arrived before the deadline. Filtering, a firewall, routing trouble, or an unreachable target may cause a timeout.

How is this different from Ping?

Ping uses ICMP. A TCP port test checks whether a specific TCP service is reachable, even when ICMP is blocked.

NETGlobal Network TestTest HTTP, TCP, Ping, Traceroute, and MTR from multiple locations worldwide.HTTPGlobal HTTP TestTest website availability and HTTP response timing from global probe locations.PINGGlobal Ping TestMeasure ICMP reachability, latency, and packet loss from global probe locations.TRACEGlobal Traceroute TestTrace network paths and hop latency from multiple global locations.IPIP Address LookupCheck public IP geolocation, ASN, network ownership, and reverse DNS.