Are you running any extenders on your network? Found this on the web... Netgear adds _EXT to the network SSID so that you know which one to connect to as you move between wifi zones. If your modem router uses NETGEAR as its SSID, you'll need another one for the Extender, so that devices know which one to connect to. The default for Netgear is to make the new network NETGEAR_EXT.

 

 

Differnt guy same problem I don't understand how this _EXT is supposed to work, I have all my devices setup to recognize my SSID that I've always used on my Modem/Router so do I have to update all of my devices? I added a TP-LINK RE205 and 2 TL-WA855RE to my network when the _EXT jumps ahead of my normal SSID my devices indicate NO INTERNET AVAILABLE when I switch it back to my SSID everything works normally. So are the extenders working or just causing me headaches? 

Your router talks to your extender and depending on model and setup it can be wired, power line, or wireless. Your router will 'talk' to the extender which in turn sends out a WIFI signal with EXT as the default. When you have your device allowed to use both the routers SSID and the extenders SSID, it will select one and may change depending on location and signal strength. For example, You can be closer to the router but get a better signal from the extender as many things affect the WIFI signal. Most set up the extender via WIFI so it is important to be sure the extender is placed in an area where it gets a good signal from the router (not in the area where you have connections issues).