Hello BDannemiller

                                DG3270 is no more under support by Arris technical team, it has been removed from our list and since we dont have any related information about that particular model, since this modem is designed for the Internet service provider only they can assist you on this configurations and settings so we would suggest you to check with your Internet service provider for more details on this setup. Make sure you are connecting Brother HL-L2360DW  to modem 2.4 network for better connection. For more assistance you can check on arris.com/consumersupport.

You can also check to see if that router supports a static ip address or reserved ip address. If it does, put the printer under a static or reserved ip address