For anyone else experiencing this problem: I was able to solve it quite easily by sheer luck. Asterisk allows you to specify individual networks. I simply added the extra VLAN there, and it worked...

@Vincent-TP The Doorbell is from Dahua. But shouldn't the problem be the RTP packet from Asterisk to the smartphone? The doorbell and the Asterisk server are in the same VLAN.

@Vincent-TP Hi and thanks for your reply. No, I haven't. Unfortunately, I also wouldn't know which Bonjour service I should use for RTP packets.

Hi, I hope I can get some help here with setting up my network. I've already spent many hours trying, but it just won't work properly. Here's the situation: Fritzbox in front of an ER605 v2, behind...