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Guest Wifi network stuck on old DNS configuration Orbi RBR750 in AP mode
Hello everyone, I'm running into a strange DNS issue on my Orbi setup and I'm hoping someone here can help. My setup: Main router: Freebox Pop (ISP router in France) Orbi RBR750 configured...
If you set a static IP address configuration for AP mode, you can set a specific or custom DNS address to use on the RBR while its in AP mode.
Static IP Address Configuration for AP Mode | NETGEAR Communities
While in AP mode any connected clients get DNS either from the custom DNS set on the RBR explicitly or if dynamically, will come from the host router up stream that is set there or automatic detected from the ISP. I believe any Guest Network side of things would also be automatic from the host router. Not sure if setting static and explicit DNS on the RBR in AP mode changes for the Guest Network side of the RBR.
If anything factory reset the RBR and setup from scratch with a ethernet PC and set up DNS there, then change to AP mode and test.
Sorry it took so long. (Dentist was SLOW.)
Orbi 750 is connected to my primary network and received IP 192.168.1.71 as LAN IP address.
Orbi 750 is in Access Point (AP) mode.
Started Wireshark on Windows laptop, set to display DHCP packets.
With Wireshark running, connected laptop to Guest WiFi on the Orbi 750.
The Orbi 750 responded with this DHCP offer:
Internet Protocol Version 4, Src: 192.168.2.1, Dst: 192.168.2.12
User Datagram Protocol, Src Port: 67, Dst Port: 68
Dynamic Host Configuration Protocol (Offer)
Message type: Boot Reply (2)
Hardware type: Ethernet (0x01)
Hardware address length: 6
Hops: 0
Transaction ID: 0x35c8cdf8
Seconds elapsed: 0
Bootp flags: 0x0000 (Unicast)
Client IP address: 0.0.0.0
Your (client) IP address: 192.168.2.12
Next server IP address: 0.0.0.0
Relay agent IP address: 0.0.0.0
Client MAC address: Intel_13:ef:7f (38:7a:0e:13:ef:7f)
Client hardware address padding: 00000000000000000000
Server host name not given
Boot file name not given
Magic cookie: DHCP
Option: (53) DHCP Message Type (Offer)
Length: 1
DHCP: Offer (2)
Option: (54) DHCP Server Identifier (192.168.2.1)
Length: 4
DHCP Server Identifier: 192.168.2.1
Option: (51) IP Address Lease Time
Length: 4
IP Address Lease Time: 30 minutes (1800)
Option: (1) Subnet Mask (255.255.255.0)
Length: 4
Subnet Mask: 255.255.255.0
Option: (3) Router
Length: 4
Router: 192.168.2.1
Option: (6) Domain Name Server
Length: 4
Domain Name Server: 192.168.1.1
Option: (255) End
Option End: 255
Notice line 12, the DHCP server on the Orbi 750 has assigned IP 192.168.2.12 to the laptop.
Line 23, the DHCP server is clearly the Orbi 750 at 192.168.1.1.
Line 29, the IP subnet mask is as expected 255.255.255.0
Line 34, the path to the internet (router) is 192.168.2.1, which is the LAN IP of the 750 router on the Guest WiFi. i.e. "Guest WiFi devices reach the internet through ME."
Line 37, the DNS server is located at 192.168.1.1, i.e. the primary router.
Thus, although the FreeBox DHCP server may have the ability to customize the DNS server list sent to devices over DHCP, the DHCP server which is built into the Orbi 750 router, even when in AP mode, sends only the IP address of the primary network router.
On a side note, since Orbi routers block devices connected to the Guest WiFi network from communicating with the primary network (except it seems from the LAN IP of the primary router), it would seem to be impossible for any device connected to the Guest WiFi to perform DNS lookups using a DNS server that is part of the primary network.