Which IP address is invalid?

Invalid IP address - Strange WiFi problem

Don't forget that both modem and router have 2 different IPs. The network should currently look like this:


You should be able to deactivate the DHCP server in the red network, i.e. from the modem, because it only ever gives the router an IP anyway. Then of course you have to set the IP addresses yourself (IP, subnet, gateway, DNS) on the WAN port of the router (i.e. the one to the modem). It is important that - if you deactivate DHCP on the modem - you have to connect a PC directly to the modem because the router no longer has a connection.

In any case, you can rule out DHCP conflicts in this way (I'm actually not sure whether the router is now forwarding DHCP broadcasts or not, but safe is safe and the DHCP server doesn't do much).

I would also be interested in what happens when the DHCP address expires. According to your copy from the router status, this should be in less than 55 minutes. This means that the IP becomes invalid and the router has to get a new one. Probably the same again, but for at least a short time it has no IP and so no PC should be able to access the Internet during that time.

Or back to the real problem. You can also give a static IP to a client despite an active DHCP server. Does that work with the notebook?