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Forum Discussion
Devices pulling invalid IP Addresses and losing connection
Need help. I have CM1000 cable modem and RBR50 Orbi mesh network with Xfinity (Comcast) internet service.
2 weeks ago I installed a new entertainment center and needed to unplug modem and router and reconnect. Soon after reconnecting and back to normal devices started randomly losing connection and some devices no longer able to gain connection. After several calls to Xfinity and Netgear it was discovered that some devices are referencing invalid IP address starting with 172.16.12. After several more calls, router resets and multiple other troubleshooting steps the problem returns.
Netgear is saying that Xfinity is not providing valid IP and Xfinity is saying that it is a network problem.
I'm at wits end and I do not want to give in and get the Xfinity network system.
Thanks,
Chad
6 Replies
The CM1000 is a "plain modem". All it does is interface between the coax cable system and the ethernet router system.
What is supposed to happen is the Orbi asks for an IP address and the cable system returns a "public" IP address for the Orbi to use.
This will be found on the Orbi web interface, http://orbilogin.net. Click on the "Advanced" tab and the "Internet block will show this public IP address.
The Orbi assigns "private" IP addresses to every device that asks for one. This is controlled on the Advanced Tab, Setup, LAN Setup. Normally, the Orbi assigns itself the address 192.168.1.1 and gives out addresses from the "pool" to devices. (There is a method to assign specific IP addresses to individual devices on the LAN setup page as well.)
If some devices are getting private addresses that begin with 172.16, then there is another device on the network that is responding to DHCP requests. Perhaps the new entertainment center has an option to act as an address server?
My suggestion is to turn off the entertainment center (the last thing added to the network). Turn off the CM1000 modem and Orbi.
Turn on the CM1000 and wait for it to "settle down". Turn on the Orbi, and see what happens. If everything returns to normal, it's time to check into the entertainment center configuration. (I would say, "slap it upside the head", but that reflects badly on my red nect roots.)
As well as giving it a good slap, and in line with the idea that you should check the settings on the entertainment center, it might be worth looking into setting its local IP address. (What is it by the way, maybe someone has already turned up here with issues.) Tell the entertainment center always to use the same IP address.
This is pure speculation on my part, but it can fix issues with other stuff on networks, such as printers. I am sure that CrimpOn will tell us if this is a nuts suggestion.
michaelkenward wrote:This is pure speculation on my part, but it can fix issues with other stuff on networks, such as printers. I am sure that CrimpOn will tell us if this is a nuts suggestion.
Every "permanent" device in my network has an assigned IP address, and that includes tablets and smartphones. About the only things getting IP's from the DHCP pool are gizmos that I plug in to test and then put in a box.
(Sad, also, that I cannot even spell "Red Neck" correctly.)
Thanks for the advice CrimpOn. Tried these things along with subscription to Gearhead support. Problem persists after several calls to Gearhead and Xfinity. I'm giving in and going with Xfinity system...Please don't judge me!! Ha ha.
Have a good one!
Chad
