Do I understand correctly that this PC acts as a DHCP server and distributes the IPs? If not, can you please explain this point in more detail ?
**--> No, the PC gets the IP Address from the DHCP Server in the Modem
(DHCP range in Modem is 80, starts with 192.168.0.10)
- I have a Firewall with fix IP cable connected to the modem (192.168.0.150), behind there is another PC
What kind of hardware firewall do you have? Do you give this firewall a fixed IP Adress?
--> Firewall has a fixed IP Address (192.168.0.150), and is connected to the Modem
--> Whatsoever, this is not relevant, also if i deconnect the Firewall, ich have still the same issue
Can you please give us the exact model of your NAS? You also write that you have released ports in the 60000-62000 range. Are this UDP oder IP Ports? Can you please specify which services you run on the NAS? VPN? Photostation? Videostation? etc.
--> Ports are configured as [BOTH] in the Modem
--> NAS is a Synology, but this doesnt matter, also when the NAS is not connected, the Problem is the same:
As soon as i configure a Port-Forwarding Rule in the Modem, the connected Clients do not have Internet Access.
Without this rule, everything is fine.
Based on my understandig of Port-Forwarding:
This comes only to action if you send a request from outside (WAN) on this Port to the Modem, then its forewarded to the IP Address configured in the rule.
So it should not interfere with the LAN setup, but it does.
I choose the 60K ports, because no application is using them.
I see on my client that he gets also a IPV6 Address from the DHCP Server in the Modem.
So i think the Modem is still on IPV6
Can you please check this again?