I'm currently using almost 20 IP cameras for 24/7 surveillance on Synology NAS. Sometimes (2 times during the last few months) my Internet provider (COX) runs some maintenance at night. As a result, there is no Internet for some period of time, usually for a few hours, mostly at night, when I don't know about that. In that case my XE75 based mesh simply dies, the LAN IP addresses, as well as  all LAN connections, go South, and the surveillance system fails to record anything since the IP cameras can not connect to  my NAS. Is it only my unique case or it's a general problem for all routers to lose LAN when Internet is down? How can I avoid that? I'm using fixed IP addresses on my LAN and I want the LAN to be rock solid, even if the Internet is down. Otherwise my surveillance system is worthless during these periods when Internet is down. I'm using UPS to provide robust stable power, but I cannot control Internet. How can I make the router (mesh) ignore the fact that it lost Internet connection and keep my LAN up and running?