Wed Jun 30, 2021 3:10 pm by louspag@hotmail.com
One option is to add your own router to handle this. My setup is that my provider's router forwards a range of ports directly to my d-link router, my dlink based on the port it receives forwards to the correct server/device on my network. This way the providers router does very little handling and manipulation of the ports.
providers router forwards ports 3000 to 3200 to my dlink
dlink is setup to forwards
3000 -->192.168.1.3:23424 (serviio)
3001 -->192.168.1.4:21 (ftp server)
3002 -->192.168.1.80 (iis server)
etc...
hope this helps