Linux noob here, but 18 years in Windows 
Recently installed volumio on my raspberry pi B. But once this machine comes online on LAN via wired or wireless, everyone else (all laptops/desktops/mobiles/tablets) starts hitting my router’s web interface (10.0.0.1) on every web page opened in their respective browsers. It asks for credentials, even if you put, nothing works.
My router is Netgear R7000 with UPnP enabled.
My “somewhat educated” guess is avahi-daemon on volumio (RPi) is messing up the DNS on the router. It enables volumio.local domain name on the LAN but kills everything else in the process.
Worse, every web request on the LAN seems to route through raspberry pi, but this tiny thing with only 700MHz CPU can’t handle it, resulting in lot of time outs.
Once I power off the raspberry pi and power cycle the router, everything goes back to normal.
Who is at fault? Router or raspberry pi? How to fix this?