If suffering from intermittent disconnections or NAT-like issues try disabling IP flood detection and/or firewall protection.
If you have issues connecting wireless you may want to disable a setting called XPress™ Technology. To do this click Wireless up top-> Click Advanced on the left-> Change the dropdown for XPress™ Technology to Disabled.
While this gateway is dual band, it is not able to run simultaneous 2.4 GHz and 5 GHz signals. Your choices are either to lock it to 2.4 GHz or to set it to Auto, which causes it to switch back and forth between 2.4 GHz and 5 GHz. Make sure to select 2.4 GHz.
If the firewall is set to maximum or medium security this device will give out an MTU Error.
Motorola SBG6580 (Arris Firmware)
There are currently no known issues for this device with Arris firmware.