v6 FTL returning wrong IPv6 address for host

[gothicVI]

I use the following docker-compose.yml and the debug token is https://tricorder.pi-hole.net/acycmCOw/

services:
  pihole:
    container_name: pihole
    image: pihole/pihole:latest
    hostname: raspberrypi
    # For DHCP it is recommended to remove these ports and instead add: network_mode: "host"
    ports:
      # DNS Ports
      - "53:53/tcp"
      - "53:53/udp"
      - "8090:80/tcp"
      - "8091:443/tcp"
      # Uncomment the below if using Pi-hole as your DHCP Server
      # - "67:67/udp"
    environment:
      TZ: "Europe/Berlin"
      FTLCONF_webserver_api_password: ""
      # If using Docker's default `bridge` network setting the dns listening mode should be set to "all"
      FTLCONF_dns_listeningMode: "all"
      FTLCONF_dns_reply_host_IPv4: "192.168.178.2"
      FTLCONF_dns_reply_host_IPv6: "fd00::3ee9:3bb4:e994:500c"
    # Volumes store your data between container upgrades
    volumes:
      - "./etc-pihole:/etc/pihole"
    cap_add:
      # See https://github.com/pi-hole/docker-pi-hole#note-on-capabilities
      # Required if you are using Pi-hole as your DHCP server, else not needed
      # - NET_ADMIN
      # Required if you are using Pi-hole as your NTP client to be able to set the host's system time
      # - SYS_TIME
      # Optional, if Pi-hole should get some more processing time
      - SYS_NICE
    restart: unless-stopped
    networks:
      - pi-hole

networks:
  pi-hole:  # Defines a custom network named "pihole_network"
    driver: bridge  # Uses the bridge driver (default for Docker networks)
    enable_ipv6: true  # Enables IPv6 support for this network
    ipam:  # IP Address Management (IPAM) configuration
      driver: default  # Uses Docker's default IPAM driver

The container addresses also showing up in the ui are 172.21.0.2 and fd3b:2b2d:793a::2 or fe80::184a:9ff:feaa:bb18. The addresses assigned to the host via my router are 192.168.178.2 and fd00::3ee9:3bb4:e994:500c which are also added as local DNS entries and as environmental variables via the docker-compose.yml.

However, when querying the host I get the container address instead of the assigned address.
From the host:

$ nslookup raspberrypi 
Server:		192.168.178.2
Address:	192.168.178.2#53

Name:	raspberrypi
Address: 192.168.178.2
Name:	raspberrypi
Address: fd3b:2b2d:793a::2

$ nslookup pi.hole
Server:		192.168.178.2
Address:	192.168.178.2#53

Name:	pi.hole
Address: 192.168.178.2
Name:	pi.hole
Address: fd3b:2b2d:793a::2

$ nslookup 192.168.178.2
2.178.168.192.in-addr.arpa	name = raspberrypi.

$ nslookup fd3b:2b2d:793a::2
2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.a.3.9.7.d.2.b.2.b.3.d.f.ip6.arpa	name = pi.hole.

$ nslookup fd00::3ee9:3bb4:e994:500c
c.0.0.5.4.9.9.e.4.b.b.3.9.e.e.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.f.ip6.arpa	name = raspberrypi.

From another host in the network:

$ nslookup raspberrypi
Server:		192.168.178.2
Address:	192.168.178.2#53

Name:	raspberrypi
Address: 192.168.178.2
Name:	raspberrypi
Address: fd3b:2b2d:793a::2

$ nslookup pi.hole
Server:		192.168.178.2
Address:	192.168.178.2#53

Name:	pi.hole
Address: 192.168.178.2
Name:	pi.hole
Address: fd3b:2b2d:793a::2

$ nslookup 192.168.178.2
2.178.168.192.in-addr.arpa	name = raspberrypi.

$ nslookup fd3b:2b2d:793a::2
2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.a.3.9.7.d.2.b.2.b.3.d.f.ip6.arpa	name = pi.hole.

$ nslookup fd00::3ee9:3bb4:e994:500c
c.0.0.5.4.9.9.e.4.b.b.3.9.e.e.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.f.ip6.arpa	name = raspberrypi.

From the running container:

# nslookup raspberrypi
Server:		127.0.0.11
Address:	127.0.0.11#53

Non-authoritative answer:
Name:	raspberrypi
Address: 172.21.0.2
Name:	raspberrypi
Address: fd3b:2b2d:793a::2

# nslookup pi.hole
Server:		127.0.0.11
Address:	127.0.0.11#53

Name:	pi.hole
Address: 192.168.178.2
Name:	pi.hole
Address: fd3b:2b2d:793a::2

# nslookup 172.21.0.2
2.0.21.172.in-addr.arpa	name = pihole.pi-hole_pi-hole.

Authoritative answers can be found from:

# nslookup 127.0.0.11
** server can't find 11.0.0.127.in-addr.arpa: NXDOMAIN

# nslookup 127.0.0.1
1.0.0.127.in-addr.arpa	name = localhost.

# nslookup 192.168.178.2
2.178.168.192.in-addr.arpa	name = raspberrypi.

# nslookup fd3b:2b2d:793a::2
2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.a.3.9.7.d.2.b.2.b.3.d.f.ip6.arpa	name = pihole.pi-hole_pi-hole.

Authoritative answers can be found from:

# nslookup fd00::3ee9:3bb4:e994:500c
c.0.0.5.4.9.9.e.4.b.b.3.9.e.e.3.0.0.0.0.0.0.0.0.0.0.0.0.0.0.d.f.ip6.arpa	name = raspberrypi.

This also shows that there seems to be an issue with the assigned IPv4 address for localhost as described in #1729. It should read 127.0.0.1 and not 127.0.0.11 or am I wrong here? (This should be unrelated to the issue though)

This is a: Bug

Details

Related Issues

• I have searched this repository/Pi-hole forums for existing issues and pull requests that look similar

How to reproduce the issue

1. Environment data

• Operating System: Rasbian
• Hardware: RasPi 4B
• Kernel Architecture: ArmV8 64bit
• Docker Install Info and version:
  • Software source: Docker version 28.0.1, build 068a01e
  • Supplimentary Software:
• Hardware architecture: ARMv8

2. docker-compose.yml contents, docker run shell command, or paste a screenshot of any UI based configuration of containers here
3. any additional info to help reproduce

These common fixes didn't work for my issue

• I have tried removing/destroying my container, and re-creating a new container
• I have tried fresh volume data by backing up and moving/removing the old volume data
• I have tried running the stock docker run example(s) in the readme (removing any customizations I added)
• I have tried a newer or older version of Docker Pi-hole (depending what version the issue started in for me)
• I have tried running without my volume data mounts to eliminate volumes as the cause

If the above debugging / fixes revealed any new information note it here.
Add any other debugging steps you've taken or theories on root cause that may help.

[gothicVI]

Anyone?

[yubiuser]

How does your /etc/hosts look inside your container?
What is the corresponding log /var/log/pihole/pihole.log when querying for raspberrypi?

[gothicVI]

Thanks for taking a look. Here you go:

raspberrypi:/# cat /etc/hosts 
127.0.0.1	localhost
::1	localhost ip6-localhost ip6-loopback
fe00::	ip6-localnet
ff00::	ip6-mcastprefix
ff02::1	ip6-allnodes
ff02::2	ip6-allrouters
172.21.0.2	raspberrypi
fd3b:2b2d:793a::2	raspberrypi

and I assume you mean query from inside the container, right?

raspberrypi:/# tail -n 1 /var/log/pihole/pihole.log
Mar 20 16:54:41 dnsmasq[48]: gravity blocked beacons5.gvt2.com is 0.0.0.0
raspberrypi:/# nslookup raspberrypi
Server:		127.0.0.11
Address:	127.0.0.11#53

Non-authoritative answer:
Name:	raspberrypi
Address: 172.21.0.2
Name:	raspberrypi
Address: fd3b:2b2d:793a::2

raspberrypi:/# cat /var/log/pihole/pihole.log | grep -v "personal FQDNs" # limited to entries equal to or after the above tail
Mar 20 16:54:41 dnsmasq[48]: gravity blocked beacons5.gvt2.com is 0.0.0.0
Mar 20 16:54:48 dnsmasq[48]: query[AAAA] beacons5.gvt3.com from 192.168.178.40
Mar 20 16:54:48 dnsmasq[48]: gravity blocked beacons5.gvt3.com is ::
Mar 20 16:54:48 dnsmasq[48]: query[A] beacons5.gvt3.com from 192.168.178.40
Mar 20 16:54:48 dnsmasq[48]: gravity blocked beacons5.gvt3.com is 0.0.0.0
Mar 20 16:54:58 dnsmasq[48]: query[A] pi.hole from 127.0.0.1
Mar 20 16:54:58 dnsmasq[48]: Pi-hole hostname pi.hole is 192.168.178.2
Mar 20 16:55:09 dnsmasq[48]: query[AAAA] beacons.gcp.gvt2.com from 192.168.178.40
Mar 20 16:55:09 dnsmasq[48]: cached beacons.gcp.gvt2.com is <CNAME>
Mar 20 16:55:09 dnsmasq[48]: cached beacons-handoff.gcp.gvt2.com is 2a00:1450:4008:806::2003
Mar 20 16:55:09 dnsmasq[48]: query[A] beacons.gcp.gvt2.com from 192.168.178.40
Mar 20 16:55:09 dnsmasq[48]: cached beacons.gcp.gvt2.com is <CNAME>
Mar 20 16:55:09 dnsmasq[48]: cached beacons-handoff.gcp.gvt2.com is 142.251.143.67

I'd assume the relevant ones are

Mar 20 16:54:58 dnsmasq[48]: query[A] pi.hole from 127.0.0.1
Mar 20 16:54:58 dnsmasq[48]: Pi-hole hostname pi.hole is 192.168.178.2

though I don't understand why the hostname of the raspberrypi which is also passed to the pihole instance get's changed to pi.hole.

Repeating the same but querying from the raspberry pi yields:

raspberrypi:/# tail -n 1 /var/log/pihole/pihole.log
Mar 20 17:02:32 dnsmasq[48]: cached ping.manjaro.org is 2a01:4f8:c0c:51f3::1
pi@raspberrypi:~ $ nslookup raspberrypi 
Server:		192.168.178.2
Address:	192.168.178.2#53

Name:	raspberrypi
Address: 192.168.178.2
Name:	raspberrypi
Address: fd3b:2b2d:793a::2

raspberrypi:/# cat /var/log/pihole/pihole.log | grep -v "personal FQDNs" # limited to entries equal to or after the above tail
Mar 20 17:02:32 dnsmasq[48]: cached ping.manjaro.org is 2a01:4f8:c0c:51f3::1
Mar 20 17:02:47 dnsmasq[48]: query[A] raspberrypi.fritz.box from 192.168.178.2
Mar 20 17:02:47 dnsmasq[48]: cached raspberrypi.fritz.box is NXDOMAIN
Mar 20 17:02:47 dnsmasq[48]: query[A] raspberrypi from 192.168.178.2
Mar 20 17:02:47 dnsmasq[48]: Pi-hole hostname raspberrypi is 192.168.178.2
Mar 20 17:02:47 dnsmasq[48]: query[AAAA] raspberrypi from 192.168.178.2
Mar 20 17:02:47 dnsmasq[48]: Pi-hole hostname raspberrypi is fd3b:2b2d:793a::2

finally, querying from another host in the network:

raspberrypi:/# tail -n 1 /var/log/pihole/pihole.log
Mar 20 17:05:19 dnsmasq[48]: cached dashapi.gleap.io is 164.90.240.143
$ nslookup raspberrypi
Server:		192.168.178.2
Address:	192.168.178.2#53

Name:	raspberrypi
Address: 192.168.178.2
Name:	raspberrypi
Address: fd3b:2b2d:793a::2

raspberrypi:/# cat /var/log/pihole/pihole.log | grep -v "personal FQDNs" # limited to entries equal to or after the above tail
Mar 20 17:05:19 dnsmasq[48]: cached dashapi.gleap.io is 164.90.240.143
Mar 20 17:05:30 dnsmasq[48]: query[A] raspberrypi.fritz.box from 192.168.178.30
Mar 20 17:05:30 dnsmasq[48]: cached raspberrypi.fritz.box is NXDOMAIN
Mar 20 17:05:30 dnsmasq[48]: query[A] raspberrypi from 192.168.178.30
Mar 20 17:05:30 dnsmasq[48]: Pi-hole hostname raspberrypi is 192.168.178.2
Mar 20 17:05:30 dnsmasq[48]: query[AAAA] raspberrypi from 192.168.178.30
Mar 20 17:05:30 dnsmasq[48]: Pi-hole hostname raspberrypi is fd3b:2b2d:793a::2

I hope this helps.

[yubiuser]

See the line in /etc/hosts within the container

fd3b:2b2d:793a::2	raspberrypi

Delete the line and see if this helps.

[gothicVI]

Commented out the line but no change from any host. The strange thing is that the IPv4 address of the container is listed there as well but that lookup works and returns the address of the raspberry pi.

[yubiuser]

Mhh... Instead of trying to debug further, how about forcing a reply address for IPv6?
I see you already set the reply IP, but did not set forcing to true. Add this env to your compose file

• FTLCONF_dns_reply_host_force6: true

[gothicVI]

That solves it! How is this needed for v6 but not for v4? Also, is this parameter documented somewhere?

[yubiuser]

How is this needed for v6 but not for v4?

It is, but your Pi-hole returned the desired IP nevertheless. The option is then called FTLCONF_dns_reply_host_force4

Also, is this parameter documented somewhere?

It is documented in the pihole.toml file and in the web interface Settings > All settings > DNS