Good to hear.
You'll find Advanced DNS Services under Setup/Internet/Manual if you have this option.
Be ware that I have and others have seen some issues with Arris ISP Modems. Not sure exactly why these are causing problems. I do know that some of them have VoIP support and thus will have a built in router. My father has one. I was visiting and had bought a NetGear WiFi router to put on. Just connecting everything like I do at home didn't work. I actually had to MAC Clone the PC to the router before the router would get connected to the Arris modem. Very ODD and I don't like it that way.
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I would recommend a Motorola SB 6120 modem should you want to hand off the Arris some day.
Things you can turn off if your don't need them on the router, QoS, WISH, Short GI, Proctected WiFi setup. If you don't use A or B modes for WiFi then theres no reason to have the router broadcast them since there not being used. Use only the modes you really need.
Anyways, keep us posted on how it goes. Here to help if we can.