TCP Ping
Test a TCP port on any host from multiple locations worldwide and compare handshake latency and packet loss over IPv4 or IPv6.
TCP ping opens a TCP connection to the port you choose from every selected probe, so it works when a network drops ICMP. Ports are measured from the probe outward; a closed port shows as no reply rather than as a failed handshake.
FAQ
TCP ping tries to open a TCP connection to a port on the target from each probe and reports the handshake round-trip time. It is the same idea as ping, but it measures a port instead of ICMP echo.
ICMP ping sends echo requests, which many firewalls and CDNs drop or rate-limit. TCP ping performs a TCP handshake on the port you choose, so it works where ICMP is blocked and reflects what a browser actually does.
443 for HTTPS, 80 for HTTP, 22 for SSH. A closed or filtered port shows as no reply on every probe. This tool measures the handshake only, so a reply does not prove that the service behind the port is healthy.
Port Check makes a single connection from TCPLab's server and tells you whether the port is open. TCP ping runs from many public probes and shows the latency and packet loss for that port in each region.
The port may be closed or filtered, or the target may block probes. Check the port number first, then try another port or ICMP ping to see whether the host is reachable at all.
Targets can rate-limit TCP handshakes or drop them under load. A few percent is normal; 100% usually means the port or the path is filtered.
The public probe network allows 250 points per hour per IP, and each probe costs one point. Selecting fewer nodes leaves more runs; packets and port do not change the cost.
The test runs from your browser directly against the public probe network, and the target is not stored by TCPLab. A domain is first checked against TCPLab's DNS endpoint so the selected IP version is not a guaranteed failure.