Good morning,
I run a small homelab with AdGuard Home DNS proxies, using Quad9 as
upstream.
I would like to configure unbound as a fallback DNS in case Quad9 is
down. Running unbound with AGH or Pi-hole seems to be a common
configuration, but I am not sure how to do it properly, specifically
with regard to cache management.
In my case, since AGH is properly configured (min ttl, max ttl, blocking
lists…), I’d like to turn of caching in unbound at this time. My current
config (on Alpine Linux) is:
root@dns ~ $ cat /etc/unbound/unbound.conf.d/pu.conf
server:
port: 5335
do-ip6: no
verbosity: 0
edns-buffer-size: 1232
# recursive resolver
root-hints: /usr/share/dns-root-hints/named.root
# disable cache, is redundant with AdGuardHome
msg-cache-size: 0
rrset-cache-size: 0
and AGH uses 127.0.0.1:5335 as the fallback upstream.
But I still get the impression that there is caching in unbound:
root@dns ~ $ dig @127.0.0.1 -p 5335 www.thunderbird.net
; <<>> DiG 9.20.11 <<>> @127.0.0.1 -p 5335 www.thunderbird.net
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31368
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.thunderbird.net. IN A
;; ANSWER SECTION:
www.thunderbird.net. 300 IN A 104.26.2.27
www.thunderbird.net. 300 IN A 104.26.3.27
www.thunderbird.net. 300 IN A 172.67.74.82
;; Query time: 189 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1) (UDP)
;; WHEN: Sun Jul 27 15:38:20 CEST 2025
;; MSG SIZE rcvd: 96
root@dns ~ $ dig @127.0.0.1 -p 5335 www.thunderbird.net
; <<>> DiG 9.20.11 <<>> @127.0.0.1 -p 5335 www.thunderbird.net
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18346
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.thunderbird.net. IN A
;; ANSWER SECTION:
www.thunderbird.net. 296 IN A 172.67.74.82
www.thunderbird.net. 296 IN A 104.26.2.27
www.thunderbird.net. 296 IN A 104.26.3.27
;; Query time: 0 msec
;; SERVER: 127.0.0.1#5335(127.0.0.1) (UDP)
;; WHEN: Sun Jul 27 15:38:24 CEST 2025
;; MSG SIZE rcvd: 96
What am I missing here?
Regards,
-Patrick
