Conditional Forwarding partially working

[Will_P]

Hello!

I have just created a new Pi-hole setup within Docker on a RPi4. The Pi-hole is working and blocking blacklisted domains. I would like to keep my router as the DHCP server for my network. I have setup Conditional Forwarding within Pi-hole in order to fetch the local client names from the router. However, only some of the client names are being resolved. The remainder show as the local IP address of the client.

Would appreciate any help! Thanks.

For reference:
Pi-hole / Docker on Pi: 192.168.1.79
Router (DHCP Server): 192.168.1.1
Router Model: Asus XT8
Router Firmware: 3.0.0.4.388_24609

Expected Behaviour

With Conditional Forwarding activated, Pi-hole should resolve IP addresses in web portal for all clients as per router DHCP

Actual Behaviour:

Pi-hole is only resolving some client names, remainder show local IP address of client.

Debug Token:

https://tricorder.pi-hole.net/JGq9wuJb/

My Conditional Forwarding configuration:

My router DHCP configuration:

Resulting client list in Pi-hole web portal (only two client names resolved):

[Bucking_Horn]

Let's see what answers your router at 192.168.1.1 provides.

What's the result of:

nslookup 192.168.1.30 192.168.1.1

nslookup 192.168.1.128 192.168.1.1

[Will_P]

Hi Bucking_Horn

First query returns:

nslookup 192.168.1.30 192.168.1.1
Server:		192.168.1.1
Address:	192.168.1.1#53

** server can't find 30.1.168.192.in-addr.arpa: NXDOMAIN

Second query returns:

nslookup 192.168.1.128 192.168.1.1
Server:		192.168.1.1
Address:	192.168.1.1#53

** server can't find 128.1.168.192.in-addr.arpa: NXDOMAIN

For good measure I tested this on one of the clients that is reporting correctly:

nslookup 192.168.1.162 192.168.1.1
Server:		192.168.1.1
Address:	192.168.1.1#53

162.1.168.192.in-addr.arpa	name = Wills-MBP.

[Will_P]

To add to this. A bit of trial and error has shown that there are (at least) two issues that might be causing this.

1. Some clients names include spaces in their names within the router’s DHCP server. Removing spaces seems to allow pi-hole to recognise their names.

2. Quite a few devices on the network are iOS devices. There is a wi-fi setting called ‘Private Wi-Fi address’ which when activated, seems to prevent the device name being recognised in pi-hole. Is there a way I can manually bind these ios device names in pi-hole?

[Bucking_Horn]

Those nslookup results from directly querying your router at 192.168.1.1 confirm that Pi-hole's Conditional Forwarding is working correctly - it is your router that is supplying those answers, and Pi-hole's dashboard merely reflects this.

You'd have to address this at your router.

If you can't fix this at your router, you could consider to create the respective Local DNS Records via Pi-hole's UI.

Note that this approach would still require your router to play along and assign the same IP addresses to the same devices.

For any devices randomising their MAC address, make sure that such a device does support using the same randomised MAC for a specific network, or to not randomise its MAC for a specific network or not at all.