Test a specific port, scan 28 common ports, or check which self-hosted services are exposed on any host or IP address - checked from VLANlab global edge servers.
Enter a hostname or IP to check port status
This tool tests whether a TCP port is reachable on any public host or IP address. Connections are made from VLANlab's edge servers, so the result reflects what the internet sees - not what your local network or ISP allows outbound.
Open - a full TCP handshake completed successfully. Something is actively listening on that port and accepted the connection.
Closed - the host is reachable but immediately sent a TCP RST (reset) packet, refusing the connection. The host is online; it just has nothing running on that port, or a local firewall is rejecting it.
Warning (timeout) - no response at all after 5 seconds. The most common cause is a network firewall silently discarding the packets rather than refusing them. This is different from "closed": with closed, the host responds (even if negatively); with timeout, there is simply no answer.
The self-hosted scan checks the default ports for popular self-hosted applications - Home Assistant, Jellyfin, Plex, Grafana, Gitea, Nextcloud and more. Use it to quickly verify which of your services are reachable from the public internet, or to confirm that a reverse proxy is correctly routing traffic.
The Reference tab lists well-known TCP and UDP ports with their standard service names and descriptions. Search by port number or service name to quickly identify what runs on any port.