I searched for hours before posting my original post. As soon as I post it I found the answer on my specific router. From NETGEAR support:
Some routers allow you to configure the router as a wireless access point (AP) to extend your wireless range. It will then act as a simple wireless gateway and its sole purpose is to provide a wireless connection. Note that once a router becomes an access point, it will lose router functions such as port forwarding and DHCP server. This article applies to the following routers:
WNDR3800
WNDR4000
WNDR4500
WNDR4500v2
I guess I’ll hook up a spare network switch and then split OS and security system off of it.
I hope this helps others with the same issue.