Review on 💨 ARRIS Surfboard TM822R - Docsis 8X4 Cable Modem/Telephone Certified for XFINITY | Download Speed: Up to 343 Mbps by Fritz Wiest

As a cable modem, this device will function properly. Fast Comcast/Xfinity installation and authorization. HOWEVER, for some strange reason, Arris decided to build a DHCP server into the modem. The modem address is 192.168.100.1 and cannot be changed. The DHCP service assigns addresses in the 192.168.100.XX pool, which makes no sense. Since it's just a modem, you'll need to use it with a router so you have local addresses and a firewall. When I set my router to talk to this modem, my router's DHCP fought with the modem's DHCP. My router was in a different address pool, and many of my computers and devices ended up in the (invalid) modem pool. To bypass that dumb modem's DHCP, I had to add UDP blocking on port 67 to the firewall, but many routers don't offer such fine-grained control. I'm lucky enough to be using an EdgeMAX router. My old Linksys would certainly not give me this block. If your router doesn't allow you to block port 67, you *can* try setting the router address to 192.168.100.1 and the DHCP pool to 192.168.100.200. + so that when assigning an address, the modem is at least in your range of IP addresses. NOTE: The modem control panel has an Advanced tab that is disabled. Maybe there are some controls to disable DHCP.