No Internet when using Pi-Hole's DHCP

Help
1

Versions

  • Pi-hole: v5.10
  • AdminLTE: v5.12
  • FTL: v5.15

Platform

  • OS and version: Fedora Server 34
  • Platform: Raspberry Pi 4b 2Gb RAM

Expected behavior

Enable DHCP on Pi-Hole, disable DHCP on my router, and everything just works.

Actual Behaviour:

When DHCP is enabled on Pi-Hole and disabled on my router (AT&T BGW320-500), devices are served IP addresses and DNS server just fine. The only problem is that the devices then are no longer connected to the internet. Pi-Hole is receiving the requests and supposedly answering them, yet no devices work. Connecting to the DNS manually while using the router's DHCP works great.

Steps to reproduce

  1. Install and set up Pi-Hole on Fedora Server 34
  2. Disable DHCP on router and enable in Pi-Hole
  3. Renew DHCP lease on computer/device (ipconfig /renew on Windows)
  4. Device loses internet connection

Debug Token:

https://tricorder.pi-hole.net/O5P8vtNJ/

Additional context

  • I initially installed Pi-Hole on Fedora Server 36 by bypassing the support checks and ran into no issues other than this one. Thinking that this might be the source of my problems I started from scratch with Fedora Server 34, which is officially supported, and ran into the same issue.
  • My router does not support changing the DHCP's DNS even though it has a bunch of other advanced options. My theory on why is that ATT uses their own in-house DNS service to collect advertising data on their users so obviously they wouldn't want anybody circumventing that
2

Try releasing the lease. A renew would try to use the same leased address and the Pi-hole DHCP does not have any record of it.

3

Sorry, I should've clarified that I did that as well as flushing my DNS by running ipconfig /release and ipconfig /flushdns

5

Which IP address do the clients have? Do they have Pi-hole as the sole DNS server?

6

And please double check that you are using Pi-hole's DHCP. The debug log you provided does not have that enabled.

*** [ DIAGNOSING ]: Setup variables
    BLOCKING_ENABLED=true
    PIHOLE_INTERFACE=eth0
    IPV4_ADDRESS=192.168.1.204/24
    IPV6_ADDRESS=2600:1700:9251:2690:decf:dff2:80eb:f6
    PIHOLE_DNS_1=8.8.8.8
    PIHOLE_DNS_2=8.8.4.4
    QUERY_LOGGING=true
    INSTALL_WEB_SERVER=true
    INSTALL_WEB_INTERFACE=true
    LIGHTTPD_ENABLED=true
    CACHE_SIZE=10000
    DNS_FQDN_REQUIRED=true
    DNS_BOGUS_PRIV=true
    DNSMASQ_LISTENING=local
    **DHCP_ACTIVE=false**
    DHCP_START=192.168.1.201
    DHCP_END=192.168.1.251
    DHCP_ROUTER=192.168.1.1
    DHCP_LEASETIME=24
    PIHOLE_DOMAIN=lan
    DHCP_IPv6=true
    DHCP_rapid_commit=true
7

Oh sorry, the debug log was with it disabled. Here's the new one: https://tricorder.pi-hole.net/ysNCUzbK/

When running the debug with DHCP on, I noticed that it errored on the default gateway and provided a link to this. The website told me to set my default gateway to my router's default gateway. I have tried this before to no avail on Fedora Server 36 as it seemed to cause any DHCP request to time out. But I decided to try it again as I haven't tried it on Fedora Server 34 yet and I hadn't found anything that told me to set this to my router's default gateway until then (yes, I looked for probably half an hour and never found that site). And it seems to have worked! I have no idea if it not working before was due to being on Fedora 36 or from a configuration error, but it now works. I'm surprised that no one mentioned this in the numerous Pi-Hole DHCP tutorials I read. Thanks for the help!

9

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