Hmmm habe von Synology Support folgende Mail bekommen, die haben mir bei der Einrichtung etwas geholfen. Ich habe ihn gefragt warum es funktioniert, obwohl die Ports zu sind:
Thanks for your inquiry.
This is normal for a "default server" setting on your router.
As I mentioned,
I add the setting of router, "default server" to your DS's ip, then it works.
I don't know why but it is a workaround.
It would be possbile to influence your port forward policy ( forward to your DS).
As a default server, that is what we call "DMZ".
All connection from outside will default forward to this default server.
If there are ports not in the rules, they will be forward to this default server, that is, your DS.
Thus you don't set those ports, they could still reach your DS.
You could set another firewall on your DS, please refer to our manual or online documents.
There are options in DSM, and you might have to spend your time on the configuration.
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Best regards,
Soll ich das so belassen? Ist das sicher?