DHCP DNS entries not automatically showing in Local DNS

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1

Expected Behaviour:

  • Home setup
  • Router: ASUS ZenWiFi AX Mini (Firmware Version:3.0.0.4.388_25163) - 192.168.0.1
  • DNS: Raspberry P1 5, Pi-Hole Server - 192.168.0.6
  • DHCP: Synology DS223j (Firmware Version:3.0.0.4.388_25163) - 192.168.0.10
  • PC: Windows 11
  • No Docker

I come from a Windows Server background (30 years) and am now retired and trying to use my Pi for DNS. In Windows hosts that had statically assigned usually had to be entered manually, while those with IPs assigned by DHCP were automatically entered in the DNS Zone.

Actual Behaviour:

I have added a few static (DHCP reserved) records and can ping these with ping -a <IP_ADDRESS>. The IP Addresses assigned by DHCP are not showing Local DNS and do not respond to pings to hostname nor with the -a switch to IP_ADDRESS. Do I have to manually add DHCP assigned entries to DNS‽

Debug Token:

Replace this text with the debug token provided from running pihole -d

2

Please follow the template and add a debug token:

Generate a debug log (sudo pihole -d), answer Y when asked to upload the file and post here just the token URL that is generated after the upload.

If you run your Pi-hole as a Docker container, use this command to generate the log:

docker exec -it <pihole-container-name-or-id> pihole -d

where you substitute <pihole-container-name-or-id> as required.

3

Hi,

Have run the command and the file is located in /var/log/pihole/pihole_debug: however, I can't open/move/upload it as I don't have permission. How do I change this behaviour (please be gentle - Windows user and learning)?

4

You don't need to move the file or try to upload it.

Just run the command again on the terminal.

When the log is completed, a prompt asking to upload it will be shown:

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Answer "Y". The log will be uploaded and you will receive an URL, like this:

https://tricorder.pi-hole.net/abcdef12/

Copy only this URL and paste it here.

5

https://tricorder.pi-hole.net/IRY7PtPJ/

6

Conditional Forwarding pointing to the NAS software doing the DHCP stuff should do the trick ?! :slight_smile:

7

Your current DHCP server is your Synology DS223j, but Pi-hole doesn't know what is configured there.

You can use the reverse DNS server option (also know as Conditional Forwarding). This option will use the other server (Synology DS223j) to return the hostnames.

On the Settings > DNS page, scroll down to the Conditional Forwarding table, then enter the server details:

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Replace teejayuu.network with your real network domain.

This will make Pi-hole ask the other server for the hostnames. If the server is able to answer reverse DNS queries, the names will be returned.

NOTE:

I noticed you configured some static DHCP leases in Pi-hole (Settings > DHCP in Pi-hole web interface), but Pi-hole DHCP server is disabled, so these entries are not loaded and they won't be used.
Pi-hole can only use these entries when its own DHCP server is running.

8

Have added the Conditional Forwarding entry and waited till all DHCP leases have renewed (24h) and the DNS entries are not showing in Local DNS.

If the server is able to answer reverse DNS queries, the names will be returned.

Does this mean I need DNS (A and PTR records) on the DHCP Server?

I noticed you configured some static DHCP leases in Pi-hole (Settings > DHCP in Pi-hole web interface), but Pi-hole DHCP server is disabled, so these entries are not loaded and they won't be used.

Remanents of earlier testing and now removed.