RBR750 Firmware Bug Report: DHCP Table Fails to Rebuild Automatically After Power Outage

How long is a typical power outage?  Many years ago, I got tired of those "mini blips" where the power goes off for a few seconds and disrupts eveything, so I now power my networking equipment (modem, router, satellites) with a small UPS that keeps them going for 30-40 minutes.  Still have to set clocks all over the house (sigh), but the overall effect is SO much less.

The reason for mentioning a network capture (such as Wireshark, which is available for Windows, MacOS, and Linux) is the possibility that some rogue device on the network is responding to the DHCP queries and your devices receive invalid information.

Total power outages are incredibly common.  Nearly every household experiences one or more every year.  If there were a coding error in the Orbi 750 product that caused every device connected to a 750 system to be unable to reconnect to the network after a power outage, every Orbi 750 owner would be clamoring.

It's all very straightforward:

• Power goes off.
• Every device in the house stops running, including networking gear and everything not connected to a UPS, or that has a battery (cell phones, tablets, many security cameras, etc.)
• When power is restored, every device goes through a boot process, which includes looking for a network information (IP address, subnet mask, gateway IP address, DNS server IP address, etc.)
  This means every device starts broadcasting DHCP discovery packets. 
  Once they are notified that there is DHCP server on the network, they broadcast a DHCP request.
  The DHCP server responds with the network information, and the device is now "on the network".

Apart from the ability to capture network traffic, do any of the devices report any details while they are not able to reconnect?  For phones, does the WiFi appear to be connected?  Anything show an IP address?

Thanks for the responses.

Just to clarify, I'm definitely no tech guru—I just stumbled onto this workaround out of sheer frustration. For my household, a power outage knocks out a large majority of our devices (everything from iPhones and Android smartphones to computers and streaming boxes like Apple TV) where they simply refuse to reconnect on their own, with the these kinds of errors:

 Connection Status Errors: Devices frequently flagged errors such as "Available via Orbi / Connection failure" and "Available via Orbi / IP configuration failure".

 In the past, I used to have to go through a full factory reset of both the Orbi router and satellite just to get things working again. Toggling the DHCP server in the local UI was a huge relief because it saves me from doing a full factory wipe every single time.

It's interesting that your setup behaves differently with a laptop, but since this sporadic issue has been happening to my RBR750 over the last year or two (spanning across both older firmware versions and the most recent V7.2.8.8_5.1.24), I really hope Netgear takes a look at the boot/startup routine in a future update so the rest of us don't have to keep manually kicking the DHCP server back into gear after an outage.

This does not match my experience.

One RBR750 and one RBS750, both running firmware v7.2.8.8_5.1.24.  There was no Factory Reset after the firmware was updated.

This RBR750 is connected to my primary network, and thus the router creates its LAN as 10.0.0.x, with DHCP pool from 10.0.0.10 through 10.0.0.254

Windows laptop connected running Wireshark to capture Ethernet connection to the router, with display filter to show only DHCP packets.

The laptop had IP of 10.0.0.13.

When the power to the router was disconnected, both the laptop and the satellite lost connection.

Power was restored, and after a few seconds the laptop began sending DHCP requests to the router (and getting no response).

Each of the requests was asking for the IP address that the laptop was using (10.0.0.13)

A total of 18 requests went by, for a total of about 100 seconds (not precise)

The 19th request got a response from the router, offering the IP 10.0.0.13.

This is exactly what one would expect to happen.

• When power is applied to the router, the Ethernet module becomes active electrically, but the router has not finished booting up and thus there are no responses.
• When the router begins to process DHCP requests, it sees that 10.0.0.13 is "available" because no other device is using it, and thus assigns it to the laptop.

Netgear61 wrote:

connected local network devices fail to automatically obtain IP addresses or reconnect to the network.

This is not my experience.  True, I have only one satellite and one laptop connected to the RBR750 router.

Does this happen to every device on the network? (both Ethernet and WiFi?)

Is it possible to set up Wireshark on one of the local connected devices and monitor what happens when power is cut to the RBR750?  It would be really interesting to see the actual DHCP traffic.

Some years ago, I had a laptop that I would "put to sleep" by closing the lid (to keep the cat off the keyboard).  When I opened the lid, it would have no internet.  Drove me CRAZY.  Had to go into the Windows Troubleshooter or restart to get a network connection.  Finally, I used Wireshark to capture the Ethernet connection and found that the laptop was broadcasting DHCP requests, the router was responding to every one, but the laptop just ignored the responses and asked again (and again, and again).  A year later, software update on the laptop and the problem went away.

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

How was the FW updated on the RBR?

Using default DHCP IP address pool range or custom? Try making the pool smaller, i.e. .100 to .200. 

Has a factory reset and setup from scratch been performed since last FW update?