said by coxta:It's not quite that easy. You can't shut off the DHCP on the modem.
DHCP isn't magic. All you have to do is create a new subnet and then your router becomes the DHCP server for that subnet while the AT&T Uverse RG is only DHCP for it's subnet which would connect to the new router's WAN port.
The DNS is:
68.94.156.1
68.94.157.1
Which are anycast IP's valid anywhere. Or you can use any DNS you want it doesn't really matter honestly for internet traffic.