Welche Ports sind auf meiner IP offen?
Ein Port, der von außen antwortet, ist ein Dienst, den das Internet erreichen kann. Dieser Test prüft Ihre eigene Adresse, von unserem Server aus, auf den wichtigsten Ports — und nur Ihre eigene: es gibt kein Feld, in das man die eines anderen eintragen könnte.
216.73.217.78
Diese Prüfung läuft gegen die Adresse, von der Ihre Anfrage kam, und gegen keine andere.
A port is the number that says which service on a machine a connection is for — 443 for HTTPS, 22 for SSH, 3389 for remote desktop. This check opens a connection from our server to your own address on the ports that matter most, and reports what happened. It runs against the address your request arrived from, and there is no field to enter anyone else's.
Reading open, closed and filtered
Open means something accepted the connection: a service on your network is reachable from the internet. Closed means the connection was actively refused, so your address is reachable but nothing is listening on that port. Filtered means nothing came back at all, which normally means a firewall or your provider is silently dropping the packets. On a typical home connection every port is filtered, because the router forwards nothing inbound — and that is the healthy result.
Which open ports deserve attention
An open 443 or 80 on a line where you deliberately run a web server is fine. An open 22, 3389, 445 or 3306 on a home connection usually is not: those are SSH, remote desktop, Windows file sharing and MySQL, and each is routinely scanned by anyone looking for something to break into. If one is open and you did not intend it, the port forwarding or UPnP rule in your router is the place to look.
Behind carrier-grade NAT
Many mobile and some fixed connections put thousands of subscribers behind one shared public address. If yours is one of those, the result here describes the carrier's edge and not your equipment, so an open port on it is not yours and closing it is not something you can do. We say so on the result when your address falls in the range reserved for this.
Häufige Fragen
Can I scan someone else's IP address here?
No. The check targets the address your own request arrived from, and there is no way to point it elsewhere. Scanning hosts you do not control is not something we will help with.
Everything is filtered. Is that bad?
It is the result most home connections should get. It means nothing inbound reaches your network, which is what a router with no port forwarding is supposed to do.
A port is open and I did not open it.
Check your router for port forwarding rules and for UPnP, which lets software on your network open ports without asking you. Turning UPnP off and reviewing the forwarding table clears up most surprises of this kind.
Why does the result differ from what a local port scanner says?
A scanner running on your own machine tests from inside the network, where the router is not in the way. This check tests from the public internet, which is the view that actually matters for exposure.