How two devices can be assigned the same IP when both are online?

Question

The image below is from my device list (Orbi 950). Two MAC address same IP.&nbsp;firmware -&nbsp;V7.2.7.15&nbsp;&nbsp;

CrimpOn · Answer

Bugger.&nbsp; Has the Orbi system been rebooted?&nbsp; (Not Factory Reset. Just powered off and back on again?)
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p.s. It is a bit unusual to connect home speaker systems and door locks to the Guest WiFi network.

plemans · Answer

The only time I've ever seen the same IP used was when one was offline and a different device was assigned the IP address.&nbsp;CrimpOn&nbsp;suggestion of trying a reboot to see if it fixes it would be my first step too.&nbsp;

yanivf · Answer

Hi&nbsp;CrimpOn&nbsp;, both the alexa and august (it's doorbell camera not their lock) are connect to guest network because I'm in the process of removing them. I also found other devices that got duplicate IPs in my home network. But guest wifi or not, the DHCP should not provide the same IPs. I haven't rebooted since I saw it. I wonder if it's firmware related. I'm on the firmware with the IPv6 issue.here are couple more examples of same IPs in the home network -&nbsp;

yanivf · Answer

Thank you both. After reboot I don't see IP duplicates.But the main point I'm trying to make is that DHCP main role is to assign unique IPs to devices.

CrimpOn · Answer

This is correct.&nbsp; If devices request an IP address using the DHCP protocol, the DHCP process is supposed to respond with an IP address that is not currently on the network, which it would discover by doing an Address Resolution Protocol (ARP) broadcast.&nbsp; However, devices which do not function as they should can interfere with the DHCP process.&nbsp; It could have been that one of those two devices ignored the ARP broadcast and did not respond, "Hey, that is the IP address I am using!"
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One of the things that annoys me about Netgear's implementation of DHCP is that it does not enforce the LAN Setup definitions.&nbsp; Suppose, for example, that I connect a new device to the network and it gets assigned 192.168.1.AAA&nbsp; I decide that "this is a camera, and I put all my cameras in a group of sequential IP addresses", so I use the LAN Setup table to assign 192.168.1.44 to that camera.&nbsp; Every time the camera DHCP lease runs out, it requests a renewal of 192.168.1.AAA and the Orbi says, "sure. keep using that."&nbsp; HEY, says the crabby grandpa.&nbsp; "I told you to assign 192.18.1.44 to that camera!!!" Grrrr.
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There are only two ways to get the camera to switch IP addresses:

Power off the camera. Set another device to a static IP address of 192.168.1.AAA and then power up the camera, or
Reboot the entire Orbi system, which will cause every device on the network to perform a new DHCP request, and "voila" the camera will get the 192.168.1.44 that I told Orbi to give it.

Either method is annoying.
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The key to investigating problems is to be able to replicate them at will. There very well may be a bug in the DHCP mechanism for the 950 product.&nbsp; If this keeps happening, please document it and (if you are within the magic "90 days of complimentary support") open a case with Netgear.

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How two devices can be assigned the same IP when both are online?

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