Arif AmiraniPi-hole on Raspberry Pi with IPv6
Setting up Pi-hole with Unbound on Raspberry Pi 4 B with IPv6 support
I’ve had a Raspberry Pi 4B sitting in my cabinet for a few months now. I dusted it off and realized that the SD card was busted. Got a replacement 64GB U3 A2 card and got it up and running with Ubuntu server. The primary intended use was to run docker with DB containers that I use for my side projects such as Postgres/MySQL/MongoDB.
My current home network consists of several routers for WiFi reachability. I try to ensure 5Ghz coverage to all my devices. Due to the concrete walls a single router does not suffice, hence a home made mesh.
The earlier ISP was a IPv4 only provider. Easy to setup. Worked out of the box. To safeguard other users of the network, I use a privacy sensitive DNS provider, Adguard. The issue with Adguard DNS was no geo proximity. It caused large ping times, as the closest CDN was never picked.
When I moved to my new ISP which supports IPv6, I decided to also deploy Pi-hole alongwith my docker containers.
Installing Pi-hole
Pi-hole is quite easy to deploy, especially with the auto install script.
curl -sSL https://install.pi-hole.net | bash
Once I followed the steps I got Pi-hole running out of the box. As suggested you have to change your router settings to send the IP address of your Pi-hole server as your local DNS. Done and done.
The Problem
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To ensure that I wasn’t fudging up DHCP/DNS discovery I used scutil:
scutil --dns
resolver #1
search domain[0] : lan
nameserver[0] : 2405:201:xxxx:xxxx:xxx:xxxx:4209:2091
nameserver[1] : fe80::a204:60ff:fe43:3005%en0
nameserver[2] : 192.168.2.50
if_index : 6 (en0)
flags : Scoped, Request A records, Request AAAA records
reach : 0x00020002 (Reachable,Directly Reachable Address)
IPv4 looked good. 192.168.2.50 is the IP of my pi-hole server.
However, the IPv6 didn’t belong to pi-hole. The default ISP setting was to use stateless IPv6 config and DNS was being advertised by the router. It was using my upstream DNS (ISP) server.
To fix this, I made the following changes:
IPv6 on pi-hole
- Get your Ipv6 address for pi-hole
ip addr show
- Enable IPv6 support on pi-hole
- Set the
IPV6_ADDRESSadd/etc/pihole/setupVars.conf
This should’ve already been done during the installation of pi-hole but if isn’t, you can manually set it up using the address above
IPV4_ADDRESS=192.168.2.50/24
IPV6_ADDRESS=2405:xxx:xxxx:xxxx::50/64
A neat trick I learnt while assigning static IPv6 addresses is to the use the same suffix as IPv4. Easy to remember and deal with.
Restart FTL:
systemctl restart pihole-FTL
- Enable AAAA query analysis for Pi-hole
Pi-hole by default will only analyse A queries, so we need to add support for AAAA.
DBINTERVAL=60
MAXDBDAYS=7
AAAA_QUERY_ANALYSIS=yes
PRIVACYLEVEL=0
I also added a throttling parameters to not wear out the SD Card.
- Refresh Pi-hole
Reboot the server. Fetch gravity lists again
pihole -g
- Stateful DHCPv6
My attempts at trying to get DHCP v4 and v6 from pi-hole failed. This is probably due to wrong assumptions of SLAAC + RA.
- Debug Pi-hole
At the end I made sure everything is kosher by running diagnosis on Pi-hole
pihole -d
Setting up Unbound
I do not like using any of the open DNS servers. They have their place and provide a lot of value but it’s not for me. I prefer a combo of ad-block and recursive DNS. Unbound works perfectly with Pi-hole. Setting it up is again very simple.
apt install unbound
Update the unbound config to support Pi-hole
/etc/unbound/unbound.conf.d/pi-hole.conf
Make a note of the port, the default port 53 is used by Pi-hole and must be changed.
server:
interface: 0.0.0.0
interface: ::0
port: 5335
access-control: 192.168.2.0/24 allow
access-control: 127.0.0.0 allow
access-control: 2001:db8:dead:beef::/48 allow
# unbound optimisation
num-threads: 4
msg-cache-slabs: 16
rrset-cache-slabs: 16
infra-cache-slabs: 16
key-cache-slabs: 16
outgoing-range: 206
so-rcvbuf: 4m
so-sndbuf: 4m
so-reuseport: yes
rrset-cache-size: 100m
msg-cache-size: 50m
# unbound security
do-ip4: yes
do-ip6: yes
do-udp: yes
do-tcp: yes
cache-max-ttl: 86400
cache-min-ttl: 3600
hide-identity: yes
hide-version: yes
minimal-responses: yes
prefetch: yes
use-caps-for-id: yes
verbosity: 1
harden-glue: yes
harden-dnssec-stripped: yes
# download from ftp://ftp.internic.net/domain/named.cache
# root-hints: "/var/lib/unbound/root.hints"
# Ensure privacy of local IP ranges
private-domain: "lan"
private-address: 192.168.0.0/16
private-address: 169.254.0.0/16
private-address: 172.16.0.0/12
# private-address: 10.0.0.0/8
private-address: fd00::/8
private-address: fe80::/10
Tweak it as per your needs and restart Unbound
systemctl restart unbound
Check unbound
Will pass:
root@pi-desktop:~# dig sigok.verteiltesysteme.net @127.0.0.1 -p 5335
; <<>> DiG 9.16.6-Ubuntu <<>> sigok.verteiltesysteme.net @127.0.0.1 -p 5335
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48863
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;sigok.verteiltesysteme.net. IN A
;; ANSWER SECTION:
sigok.verteiltesysteme.net. 3600 IN A 134.91.78.139
;; Query time: 499 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1)
;; WHEN: Tue Feb 23 08:53:17 IST 2021
;; MSG SIZE rcvd: 71
Will fail:
root@pi-desktop:~# dig sigfail.verteiltesysteme.net @127.0.0.1 -p 5335
; <<>> DiG 9.16.6-Ubuntu <<>> sigfail.verteiltesysteme.net @127.0.0.1 -p 5335
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 56203
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;sigfail.verteiltesysteme.net. IN A
;; Query time: 1147 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1)
;; WHEN: Tue Feb 23 08:53:43 IST 2021
;; MSG SIZE rcvd: 57
DHCP Confirmation
At least for IPv4, you can run the debug tool to make sure DHCP is correct.
root@pi-desktop:~# pihole-FTL dhcp-discover
Scanning all your interfaces for DHCP servers
Timeout: 10 seconds
* Received 301 bytes from eth0:192.168.2.1
Offered IP address: 192.168.2.113
Server IP address: 192.168.2.1
Relay-agent IP address: N/A
BOOTP server: (empty)
BOOTP file: (empty)
DHCP options:
Message type: DHCPOFFER (2)
server-identifier: 192.168.2.1
lease-time: 3600 ( 1h )
renewal-time: 1800 ( 30m )
rebinding-time: 3150 ( 52m 30s )
netmask: 255.255.255.0
broadcast: 192.168.2.255
router: 192.168.2.1
dns-server: 192.168.2.50
dns-server: 192.168.2.50
domain-name: "lan"
--- end of options ---
Switching Pi-hole to use unbound
Disable all Upstream DNS servers and add custom DNS that you setup for Unbound. Use the loopback addresses for Unbound:
IPv4 127.0.0.1#5335
IPv6 ::1#5335
That should be it! Hope you enjoyed reading the article.