Port connectivity
TCP Port Check
A TCP check opens a real connection to a specific port and reports whether it is accepted. Unlike ping, it confirms an actual service is listening — the best signal that a server is truly reachable on, say, port 443 (HTTPS) or 22 (SSH).
Run a TCP Check test →What it measures
- Whether the port is open, closed or filtered
- Connection (handshake) time in milliseconds
- Per-location reachability across all five regions
How to read the results
- “Open” means a service accepted the TCP handshake on that port.
- “Closed / filtered” means nothing is listening or a firewall dropped the attempt.
- Differences between regions can reveal geo-blocking or regional outages.
Frequently asked questions
What's the difference between TCP check and ping?
Ping uses ICMP to measure latency; a TCP check verifies a specific port actually accepts connections — a stronger reachability signal.
Which port should I test?
443 for HTTPS, 80 for HTTP, 22 for SSH, 25/465/587 for mail, 3306 for MySQL, and so on.