It's a bug. You can try the workarounds, but the bug will typically return between 1 week and 3 months. The bug has a mind of its own. Not real predictable. Some people can never shake the bug no matter what they try.
Start by resetting to factory defaults and add your devices one-by-one and use dhcp reservations.
Here's the EA6500 link. You'll have to search for EA4500 and E4200v2 thread, but it's the same bug. And same unpredictable workaround and results. Many people just threw in towel and bought a different router from different vendor.
http://community.linksys.com/t5/Wireless-Routers/EA6500-Multiple-devices-under-one-device/td-p/572310
Start by resetting to factory defaults and add your devices one-by-one and use dhcp reservations.
Here's the EA6500 link. You'll have to search for EA4500 and E4200v2 thread, but it's the same bug. And same unpredictable workaround and results. Many people just threw in towel and bought a different router from different vendor.
http://community.linksys.com/t5/Wireless-Routers/EA6500-Multiple-devices-under-one-device/td-p/572310