Using the Nighthawk M6 Pro to feed internet into router

[NismoZ]

Trying to use the M6 Pro to feed internet access into my home router (LinkSys EA8500) as a backup for my cable modem. I can get everything to work fine in this setup, but I notice that as soon as I hook my router ethernet cable into the M6 Pro, that my local IP address scheme gets switched from 192.168.1.x to a range of 1.1xx.1.1. Why is my router making this change as soon as I plug the ethernet cable into the M6 Pro for internet access? As a test, I changed the M6 Pro's gateway to 192.168.1.2 to avoid any conflicts with the routers gateway of 192.168.1.1, but my router still changed its local IP ranges.

 

[NismoZ]

Found the resolution. I set the gateway on the M6 Pro to 192.168.2.1 which allowed me to keep the gateway on my router as its default 192.168.1.1. This resulted in no conflict have my router automatically changing its gateway and dhcp IP range.