Queries for local DNS records exploding

[deHakkelaar]

The issue I am facing:

Anyone else noticed the TTL for local DNS records being zero seconds with one of the later updates?

pi@ph5b:~ $ dig @localhost nas.home.dehakkelaar.nl a

; <<>> DiG 9.16.22-Raspbian <<>> @localhost nas.home.dehakkelaar.nl a
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54957
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;nas.home.dehakkelaar.nl.            IN      A

;; ANSWER SECTION:
nas.home.dehakkelaar.nl.     0       IN      A       10.0.0.3

;; Query time: 9 msec
;; SERVER: ::1#53(::1)
;; WHEN: Tue Jul 05 17:18:14 CEST 2022
;; MSG SIZE  rcvd: 63

The current release is missing the local-ttl=2 directive that used to exist before.
When adding that directive in again:

pi@ph5b:~ $ sudo nano /etc/dnsmasq.d/99-my-settings.conf
local-ttl=2

pi@ph5b:~ $ pihole-FTL --test
dnsmasq: syntax check OK.

pi@ph5b:~ $ sudo service pihole-FTL reload
pi@ph5b:~ $

I get a non zero TTL returned again:

pi@ph5b:~ $ dig @localhost nas.home.dehakkelaar.nl a

; <<>> DiG 9.16.22-Raspbian <<>> @localhost nas.home.dehakkelaar.nl a
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51186
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;nas.home.dehakkelaar.nl.            IN      A

;; ANSWER SECTION:
nas.home.dehakkelaar.nl.     2       IN      A       10.0.0.3

;; Query time: 89 msec
;; SERVER: ::1#53(::1)
;; WHEN: Tue Jul 05 17:33:01 CEST 2022
;; MSG SIZE  rcvd: 63

Client hostnames that are advertised via DHCP seems not effected regardless of that added directive:

pi@ph5b:~ $ dig @localhost avr.home.dehakkelaar.nl a

; <<>> DiG 9.16.22-Raspbian <<>> @localhost avr.home.dehakkelaar.nl a
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13571
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;avr.home.dehakkelaar.nl.            IN      A

;; ANSWER SECTION:
avr.home.dehakkelaar.nl.     2       IN      A       10.0.0.9

;; Query time: 9 msec
;; SERVER: ::1#53(::1)
;; WHEN: Tue Jul 05 17:39:58 CEST 2022
;; MSG SIZE  rcvd: 63

I noticed these DNS queries exploding when logged into my Syno NAS web GUI.

Details about my system:

pi@ph5b:~ $ cat /proc/device-tree/model
Raspberry Pi Model B Rev 2

pi@ph5b:~ $ lsb_release -d
Description:    Raspbian GNU/Linux 11 (bullseye)

pi@ph5b:~ $ pihole -v
  Pi-hole version is v5.10 (Latest: v5.10)
  AdminLTE version is v5.12 (Latest: v5.12)
  FTL version is v5.15 (Latest: v5.15)

Pi-hole DHCP service active.
Created below DNS record via the web GUI:

pi@ph5b:~ $ cat /etc/pihole/custom.list
[..]
10.0.0.3 nas.home.dehakkelaar.nl

What I have changed since installing Pi-hole:

Added Unbound using the offical guide.
Added my own directive to advertise two Pi-hole DNS servers via DHCP:

pi@ph5b:~ $ sudo grep -v '#\|^$' -R /etc/dnsmasq.*
[..]
/etc/dnsmasq.d/10-dhcp-dns.conf:dhcp-option=option:dns-server,10.0.0.2,10.0.0.4

[Bucking_Horn]

@deHakkelaar

Anyone else noticed the TTL for local DNS records being zero seconds with one of the later updates?

I'm puzzled that didn't hit you earlier, as that should have been the case since Pi-hole FTL v5.10.1, Web v5.7 and Core v5.5 released from September 2021 (emphasis mine):

@DL6ER

Handle TTL for blocked queries separately
You can now set your own local-ttl value if you want to.
Note that this changes the default TTL for local hostnames from two seconds to “do not cache” (dnsmasq’s default). If you want to avoid this, create a file like /etc/dnsmasq.d/99-local-ttl.conf and add a line like local-ttl=60 for one minute TTL on local hostnames.

[deHakkelaar]

Ahahaha, I didnt update for a while and recently hastily updated without reading the release notes because I was working on supporting someone else and had to reply quickly with my versions being up to date.
My mistake

EDIT: Ow and maybe it happened already before but didnt notice

pi@ph5b:~ $ dig @localhost nas.home.dehakkelaar.nl a

; <<>> DiG 9.16.22-Raspbian <<>> @localhost nas.home.dehakkelaar.nl a
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 8052
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;nas.home.dehakkelaar.nl.            IN      A

;; ANSWER SECTION:
nas.home.dehakkelaar.nl.     60      IN      A       10.0.0.3

;; Query time: 0 msec
;; SERVER: ::1#53(::1)
;; WHEN: Tue Jul 05 19:35:19 CEST 2022
;; MSG SIZE  rcvd: 63

[deHakkelaar]

Some feedback, after about 24 hours I dont observer those queries exploding anymore when accessing my NAS GUI with the TTL set to 60 seconds.