madbrain76's profile



46 Messages

Fri, Feb 26, 2021 6:00 PM

XB6 - how to set static DHCP reservation for LAN devices ?

I have the Comcast XB6 xFi gateway configured in router mode. I have the DHCP range set to through . I'm trying to assign (private) static IPs to my (many!) LAN devices.

1) First, I go to "Connected Devices -> Devices"

2) Then I choose a device and click "Edit".

3) Then, I change the configuration from "DHCP" to "Reserved IP", choosing a new, previously unused IP address from the DHCP range,

4) I click "Save"

5) I get "Operation in progress" then after a few seconds : "Failure! Please check your inputs."


I tried to modify the DHCP range from to .

I repeated steps 1-4 above. Then I get "Reserve IP address is not in valid range: -"

I tried another IP address from the range, And now I get again "Failure! Please check your inputs".


Does this feature work at all ? And if so how ?




1 Message

3 m ago

I'm about to do a gateway swap, and found this thread. Tell me if I'm wrong - a "reserved" IP is like a static one managed by the DHCP server, asking the same IP always be held and given to the same MAC #, so the other details like gateway and DNS get updated by the router as needed. Like DHCP but with fixed number. This should work OK with devices like printers that can't be found if they get a new IP after rebooting, yes? 

I'd always try to note specifics of the device in the comment field for later troubleshooting, so I think I accidentally avoided the bug described here! Thanks for all the details on it. 

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