Hi radiorobert,

the most importent thing is, to switch from F5.2 to F5.3 (F5.2 is obsolet for about 8 years). To do that, look at ... Broadcaster's area -> Change streams´s data .There will be much better connectivity :-) Maybe portforwarding is not required.

Here you will find the router manual ...
http://setuprouter.com/router/zyxel/vmg8324-b10a/manual-2021.pdf ... page 159 describes adding of forwarding rules.

As preperation, listen any Flatcast-Stream right mouseclick in the chat rectangle, select Mapping Info. The small window displays your Local IP.

Some hints for adding a new fowarding rule:
Select Active
Service Name: FLATCAST
WAN Interface: maybe ADSL
Start Port = End Port = Translation Start Port = Translation End Port = 40123
Server IP Adress: Local IP (see above ... you should use static IPs)
Protocal: UDP

The problem is WAN IP ... we don't know the router plz. contact the support of ZYXEL

Regards

Hannes