I have an Orbi RBR760 connected to my cable modem, also Netgear.My network Gateway / DHCP is 10.0.0.x. Works as advertised, most of the time. However, I noticed a number of connected devices that have 192.168.2.x for IP addresses.192.168.2.x is not configured on any device in my network. The MAC address goes to my Orbi router. Suggestions on how I resolve this? Firmware is current, says the website.

In this case they have a CAX30. Similar to the CAX80 I have. Can run double NAT and should work. However when encountering odd LAN IP addressing problems and such, sometimes it makes things easier to put the CAX to modem only mode and then run the RBR in router mode. KISS. 😘

What Firmware version is currently loaded? v.2 is most current for the 7 series: https://community.netgear.com/t5/Orbi-WiFi-6-AX-and-WiFi-6E-AXE/New-RBR750-RBS750-Firmware-Version-4-6-8-2-Released/td-p/2217844/jump-to/first-unread-message What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too? What mode is the RBR working in? Router or AP mode? There a screen capture of what your seeing that you can post here?

What actual netgear modem is it? Usually if the router switches off the default ip address, the modem its connected to isn't just a modem, its a modem/router combo device. Its why model numbers help. If it is indeed a modem/router combo device, it causes a double nat. A double nat happens when you cascade more than 1 router. https://kb.netgear.com/30186/What-is-Double-NATFixes? There’s 3 options but only use 1. 1. Put the modem/gateway in modem only/pass through mode. This disables its routing functions. 2. Leave the modem/gateway in router mode but put the Netgears IP address into its DMZ. This forwards the data to the netgear. You can either leave the modem/gateway’s wireless enabled or disabled. Just make sure its using a different wifi channel to prevent interference. Probably not the option I'd use.3. Put the Netgear router into access point mode. This disables its routing functions. Wifi/ethernet still works but it does disable some features. https://kb.netgear.com/26765/Which-features-are-disabled-on-my-NETGEAR-router-when-it-is-set-to-AP-Mode I'd probably go with option 1 or 3.

costler wrote: My network Gateway / DHCP is 10.0.0.x. Works as advertised, most of the time. However, I noticed a number of connected devices that have 192.168.2.x for IP addresses. 192.168.2.x is not configured on any device in my network. The MAC address goes to my Orbi router. The default LAN IP subnet for Orbi routers is 192.168.1.x. When the router is connected, it requests an IP address for the WAN port. If this IP address is in the 192.168.1.x subnet, then the Orbi changes to 10.0.0.x for its LAN subnet. (That is the other private IP space.) This can be verified by checking the IP address that shows on the Orbi web interface, Advanced Home Page in the box labelled "Internet Port". There are two ways a device gets an IP address: A manual setting on the device itself (usually called a static IP). Using DHCP, where the device broadcasts a request and accepts the first DHCP server to respond. Usually, there is only one DHCP server in the local broadcast subnet (the router). Things can get really ugly when there is another DHCP server in the network. Could you please report the "internet IP" of the router? Is it possible to access any of the devices with that 192.168.2.x IP address to see what they report as their Gateway IP?

Thanks for the repliesThe Modem is a Nighthawk AX6 (CAX30). WIFI disabled (in all of the many places it shows up). I have tried to turn off the router mode, the Orbi end of things then stopped working. I had to factory reset the Nighthawk to get back online. It does have a 170.x.x.x ip address from my ISP. DHCP for the LAN is 192.168.1.x the scope allows for only two IP addresses. firmware v1.4.10.8 RBR750 is in Router mode. Firmware v4.6.5.14, one satellite. Used to have two, one refuses to do anything, so I unplugged / deleted it. DHCP scope is 10.0.0.2 - 10.0.0.77When I look at attached devices there are 6 that have 192.168.2.x for an IP address, and to add to the mystery, they all work / internet / all good. They show a gateway of 192.168.1.1 ARP -a presents me with the Orbi MAC address. What I do not have is the DHCP scope of 192.168.2.x configured on any device on the network. Even if I was, it shouldn't work. I used to be a Banyan / Cisco network engineer, so this bother me. While my Bandwidth and connectivity with the Orbi has been great, I find them extra special flakey.. I had a firmware problem last winter and Supports only answer was to do a hard reset. If I can't run this down, I may have to put the Orbi stuff on craigs list and go purchase something better.

RBR750 DHCP | NETGEAR Communities

13 Replies

FURRYe38
Guru
Jun 23, 2022
What Firmware version is currently loaded? v.2 is most current for the 7 series:

https://community.netgear.com/t5/Orbi-WiFi-6-AX-and-WiFi-6E-AXE/New-RBR750-RBS750-Firmware-Version-4-6-8-2-Released/td-p/2217844/jump-to/first-unread-message

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

What mode is the RBR working in? Router or AP mode?

There a screen capture of what your seeing that you can post here?
plemans
Guru
Jun 23, 2022
What actual netgear modem is it?
Usually if the router switches off the default ip address, the modem its connected to isn't just a modem, its a modem/router combo device.

Its why model numbers help.

If it is indeed a modem/router combo device, it causes a double nat.

A double nat happens when you cascade more than 1 router.
https://kb.netgear.com/30186/What-is-Double-NAT
Fixes? There’s 3 options but only use 1.
1. Put the modem/gateway in modem only/pass through mode. This disables its routing functions.
2. Leave the modem/gateway in router mode but put the Netgears IP address into its DMZ. This forwards the data to the netgear. You can either leave the modem/gateway’s wireless enabled or disabled. Just make sure its using a different wifi channel to prevent interference. Probably not the option I'd use.
3. Put the Netgear router into access point mode. This disables its routing functions. Wifi/ethernet still works but it does disable some features.
https://kb.netgear.com/26765/Which-features-are-disabled-on-my-NETGEAR-router-when-it-is-set-to-AP-Mode

I'd probably go with option 1 or 3.
CrimpOn
Guru
Jun 23, 2022
costler wrote:

My network Gateway / DHCP is 10.0.0.x. Works as advertised, most of the time. However, I noticed a number of connected devices that have 192.168.2.x for IP addresses.

192.168.2.x is not configured on any device in my network. The MAC address goes to my Orbi router.

The default LAN IP subnet for Orbi routers is 192.168.1.x. When the router is connected, it requests an IP address for the WAN port. If this IP address is in the 192.168.1.x subnet, then the Orbi changes to 10.0.0.x for its LAN subnet. (That is the other private IP space.) This can be verified by checking the IP address that shows on the Orbi web interface, Advanced Home Page in the box labelled "Internet Port".

There are two ways a device gets an IP address:

A manual setting on the device itself (usually called a static IP).

Using DHCP, where the device broadcasts a request and accepts the first DHCP server to respond. Usually, there is only one DHCP server in the local broadcast subnet (the router). Things can get really ugly when there is another DHCP server in the network.

Could you please report the "internet IP" of the router?

Is it possible to access any of the devices with that 192.168.2.x IP address to see what they report as their Gateway IP?
- costler
  Tutor
  Jun 23, 2022
  Thanks for the replies
  The Modem is a Nighthawk AX6 (CAX30). WIFI disabled (in all of the many places it shows up). I have tried to turn off the router mode, the Orbi end of things then stopped working. I had to factory reset the Nighthawk to get back online. It does have a 170.x.x.x ip address from my ISP. DHCP for the LAN is 192.168.1.x the scope allows for only two IP addresses. firmware v1.4.10.8
  
  RBR750 is in Router mode. Firmware v4.6.5.14, one satellite. Used to have two, one refuses to do anything, so I unplugged / deleted it. DHCP scope is 10.0.0.2 - 10.0.0.77
  When I look at attached devices there are 6 that have 192.168.2.x for an IP address, and to add to the mystery, they all work / internet / all good. They show a gateway of 192.168.1.1 ARP -a presents me with the Orbi MAC address.
  
  What I do not have is the DHCP scope of 192.168.2.x configured on any device on the network. Even if I was, it shouldn't work. I used to be a Banyan / Cisco network engineer, so this bother me.
  
  While my Bandwidth and connectivity with the Orbi has been great, I find them extra special flakey.. I had a firmware problem last winter and Supports only answer was to do a hard reset. If I can't run this down, I may have to put the Orbi stuff on craigs list and go purchase something better.
  - CrimpOn
    Guru
    Jun 23, 2022
    Wow. What a puzzle!
    
    To recap:
    
    The CAX30 WAN port has a public IP address.
    
    The CAX30 LAN port has 192.168.1.1
    
    Nothing is connected directly to the CAX30 besides the RBR750.
    
    The RBR750 WAN port has IP 192.168.1.2
    
    The RBR750 LAN port is IP 10.0.0.1
    
    The RBR750 DHCP range is 10.0.0.2 - 10.0.0.77
    
    The router Attached Devices page shows devices with both 10.0.0.x and 192.168.2.x IP addresses.
    
    When you dump the entire ARP table on a PC, there are entries with both 10.0.0.x and 192.168.2.x IP addresses.
    
    Can you share the type of devices that have 192.168.2.x IP addresses?
    
    Is the Guest WiFi network enabled?

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