NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
RBR750 DHCP
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...
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 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.
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?
I think you nailed it.
While I just looked at the list of attached devices. What type of devices? My phone, one laptop, iPad, other assorted smart switches. they are ALL on the Guest network.
So I did a search for orbi rbr 750 Guest network IP range. Appears that the guest network is responsible for the 192.168.2.x ip range. Explains why the MAC address is the RBR 750, I should have noticed that. I was hyper focused on how that IP range would even work, it would appear Netgear does it in the background. But this makes me question what the heck else is it doing all on it's own?
No double NAT issues. Tracert PC-> Obri -> Cable Modem -> ISP - > destination
Thanks
Modem mode on the CAX would be recommended. If you set this, the modem should reboot and if you power OFF the RBR while it's in router mode, it should get a clean WAN IP address from the modem. Thus by passing all the double nat issues that you seem to be having.
I recommend trying the CAX modem in modem mode and the RBR in router mode.
https://kb.netgear.com/27191/How-to-set-the-cable-modem-router-to-be-on-modem-only
costler wrote:
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.
FURRYe38 wrote:
Modem mode on the CAX would be recommended. If you set this, the modem should reboot and if you power OFF the RBR while it's in router mode, it should get a clean WAN IP address from the modem. Thus by passing all the double nat issues that you seem to be having.
A bit annoying that this is not mentioned in the CAX30 User Manual. Have no idea what this would do to the LAN Setup Table for any devices which have assigned IP addresses.
