I have been using Pihole for about 6 months without any problems. To improve privacy, i thought I would try to integrate recursive dns using unbound.
I am using Pi-hole on a Raspberry Pi 3 using the latest version of Pi-hole (PI-HOLE V5.14.2 FTL V5.20 WEB INTERFACE V5.18) and Unbound (1.13.1).
I followed the instructions in the guide: unbound - Pi-hole documentation
I got Unbound setup and i can resolve websites using dig on my pihole server. However, when I go into the Pihole UI and configure it to use unbound it I am not able to resolve any dns.
Expected Behaviour:
Upon configuring the Unbound IP and PORT in the PiHole user interface, i am expecting to be able to resolve upstream dns records through PiHole using Unbound.
Example of Unbound working:
pi@Pihole:~ $ dig google.com @127.0.0.1 -p 5335
; <<>> DiG 9.16.33-Raspbian <<>> google.com @127.0.0.1 -p 5335
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3152
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 207 IN A 172.253.115.102
google.com. 207 IN A 172.253.115.113
google.com. 207 IN A 172.253.115.138
google.com. 207 IN A 172.253.115.139
google.com. 207 IN A 172.253.115.100
google.com. 207 IN A 172.253.115.101
;; Query time: 119 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1)
;; WHEN: Tue Jan 03 21:12:40 EST 2023
;; MSG SIZE rcvd: 135
Going to the Pihole interface, I unselect the IPV4 upstream DNS servers and select the Custom 1 DNS server (IPv4) and set it to 127.0.0.1#5335
At this time, DNS does not resolve.
If I go back to the server and do another dig, that too will report s SERVFAIL
pi@Pihole:~ $ dig google.com @127.0.0.1 -p 5335
; <<>> DiG 9.16.33-Raspbian <<>> google.com @127.0.0.1 -p 5335
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 48172
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com. IN A
;; Query time: 10 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1)
;; WHEN: Tue Jan 03 21:53:34 EST 2023
;; MSG SIZE rcvd: 39
Unbound Configuration:
server:
# If no logfile is specified, syslog is used
# logfile: "/var/log/unbound/unbound.log"
verbosity: 0
interface: 127.0.0.1
port: 5335
do-ip4: yes
do-udp: yes
do-tcp: yes
# May be set to yes if you have IPv6 connectivity
do-ip6: no
# You want to leave this to no unless you have *native* IPv6. With 6to4 and
# Terredo tunnels your web browser should favor IPv4 for the same reasons
prefer-ip6: no
# Use this only when you downloaded the list of primary root servers!
# If you use the default dns-root-data package, unbound will find it automatically
#root-hints: "/var/lib/unbound/root.hints"
# Trust glue only if it is within the server's authority
harden-glue: yes
# Require DNSSEC data for trust-anchored zones, if such data is absent, the zone becomes BOGUS
harden-dnssec-stripped: yes
# Don't use Capitalization randomization as it known to cause DNSSEC issues sometimes
# see https://discourse.pi-hole.net/t/unbound-stubby-or-dnscrypt-proxy/9378 for further details
use-caps-for-id: no
# Reduce EDNS reassembly buffer size.
# IP fragmentation is unreliable on the Internet today, and can cause
# transmission failures when large DNS messages are sent via UDP. Even
# when fragmentation does work, it may not be secure; it is theoretically
# possible to spoof parts of a fragmented DNS message, without easy
# detection at the receiving end. Recently, there was an excellent study
# >>> Defragmenting DNS - Determining the optimal maximum UDP response size for DNS <<<
# by Axel Koolhaas, and Tjeerd Slokker (https://indico.dns-oarc.net/event/36/contributions/776/)
# in collaboration with NLnet Labs explored DNS using real world data from the
# the RIPE Atlas probes and the researchers suggested different values for
# IPv4 and IPv6 and in different scenarios. They advise that servers should
# be configured to limit DNS messages sent over UDP to a size that will not
# trigger fragmentation on typical network links. DNS servers can switch
# from UDP to TCP when a DNS response is too big to fit in this limited
# buffer size. This value has also been suggested in DNS Flag Day 2020.
edns-buffer-size: 1232
# Perform prefetching of close to expired message cache entries
# This only applies to domains that have been frequently queried
prefetch: yes
# One thread should be sufficient, can be increased on beefy machines. In reality for most users running on small networks or on a single machine, it should be unnecessary to seek performance enhancement by increasing num-threads above 1.
num-threads: 1
# Ensure kernel buffer is large enough to not lose messages in traffic spikes
so-rcvbuf: 1m
# Ensure privacy of local IP ranges
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
Actual Behaviour:
The browser reports DNS error. When I switch back to using UPSTREAM DNS SERVERS, everything works fine once again and I can resolved DNS through PiHole on both calling browsers and also on the Pi-Hole server via dig.
Your help is much appreciated. I used as much documentation and troubleshooting online as I can find. I have not been able to resolve this issue on my own so far. Anything you can offer for troubleshooting would be much appreciated.
. Let's see what they think about it. I however just see that