Slow DNS Resolution after installing Fresh

MKutka · July 21, 2021, 9:58pm

Expected Behaviour:

Hello,
New to Pi-Hole and looking forward to some of the functionality it has to offer. I've installed fresh on a Ubuntu 20.04.02 server running in my ESXi environment and whenever I point my PC, Macbook, etc to this new server DNS resolution slows down dramatically. I previously ran Pi-Hole as a docker pod on my Synology and noticed it also to be slow and read that others experienced this on v5.0 so I just elected to spin up a VM and see how things work on here, but same experience.

Including the debug token here:
https://tricorder.pi-hole.net/34pnia18qx

DanSchaper · July 22, 2021, 12:39am

The debug log shows that this new fresh install had some problems importing the backup.

There are no white/black entries or any custom entries now:

*** [ DIAGNOSING ]: Groups
   id    enabled  name                                                date_added           date_modified        description                                       
   ----  -------  --------------------------------------------------  -------------------  -------------------  --------------------------------------------------
   0           1  Default                                             2021-07-20 20:22:59  2021-07-20 20:22:59                                                    

*** [ DIAGNOSING ]: Domainlist (0/1 = exact white-/blacklist, 2/3 = regex white-/blacklist)

*** [ DIAGNOSING ]: Clients

*** [ DIAGNOSING ]: Adlists
   id    enabled  group_ids     address                                                                                               date_added           date_modified        comment                                           
   ----  -------  ------------  ----------------------------------------------------------------------------------------------------  -------------------  -------------------  --------------------------------------------------
   1           1  0             https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts                                      2021-05-30 18:27:55  2021-07-20 20:22:53  Migrated from /etc/pihole/adlists.list

   -----tail of error.log------
   2021-07-20 20:18:31: (server.c.1488) server started (lighttpd/1.4.55) 
   2021-07-20 20:18:35: (server.c.1970) server stopped by UID = 0 PID = 1 
   2021-07-20 20:18:35: (server.c.1488) server started (lighttpd/1.4.55) 
   2021-07-20 20:22:59: (mod_fastcgi.c.421) FastCGI-stderr: PHP Warning:  SQLite3::exec(): no such table: blacklist in /var/www/html/admin/scripts/pi-hole/php/teleporter.php on line 90
   2021-07-20 20:22:59: (mod_fastcgi.c.421) FastCGI-stderr: PHP Warning:  SQLite3::exec(): no such table: regex_blacklist in /var/www/html/admin/scripts/pi-hole/php/teleporter.php on line 90
   2021-07-20 20:22:59: (mod_fastcgi.c.421) FastCGI-stderr: PHP Warning:  Executing sudo pihole -a addcustomdns 192.168.30.5 <REDACT> failed. in /var/www/html/admin/scripts/pi-hole/php/func.php on line 79
   2021-07-20 20:22:59: (mod_fastcgi.c.421) FastCGI-stderr: PHP Warning:  SQLite3::exec(): no such table: whitelist in /var/www/html/admin/scripts/pi-hole/php/teleporter.php on line 90
   2021-07-20 20:22:59: (mod_fastcgi.c.421) FastCGI-stderr: PHP Warning:  SQLite3::exec(): no such table: regex_whitelist in /var/www/html/admin/scripts/pi-hole/php/teleporter.php on line 90
   2021-07-20 20:23:59: (server.c.1970) server stopped by UID = 0 PID = 1 
   2021-07-20 20:24:13: (server.c.1488) server started (lighttpd/1.4.55)

Can you provide some dig or nslookup results with what you are seeing?

It doesn't look like there is a DHCP server on the segment, how are you configuring your clients and what DNS servers do they show as being used?

Some basic dig pi.hole output or nslookup pi.hole would show some information for us to look at.

MKutka · July 22, 2021, 1:16am

Hey Dan,

Thanks for your response. Currently my router is handling DHCP and is handing out pi hole as the lone DNS server.

➜  ~ scutil --dns | grep nameserver
  nameserver[0] : 192.168.30.50
  nameserver[0] : 192.168.30.50

Below is the dig and nslookup from the server to pi.hole

administrator@pi-hole:~$ dig pi.hole

; <<>> DiG 9.16.1-Ubuntu <<>> pi.hole
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 32000
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;pi.hole.			IN	A

;; AUTHORITY SECTION:
.			86273	IN	SOA	a.root-servers.net. nstld.verisign-grs.com. 2021072104 1800 900 604800 86400

;; Query time: 8 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Thu Jul 22 01:09:42 UTC 2021
;; MSG SIZE  rcvd: 111

administrator@pi-hole:~$ nslookup pi.hole
Server:		1.1.1.1
Address:	1.1.1.1#53

** server can't find pi.hole: NXDOMAIN

administrator@pi-hole:~$

Thanks!

jfb · July 22, 2021, 2:08am

The client from which you ran those DNS queries is not using Pi-hole for DNS. It is using cloudflare, and Pi-hole did not answer either query.

MKutka · July 22, 2021, 2:20am

Hello,

Apologies for the confusion. The dig and nslookup I posted before were from the Ubuntu server running Pi-Hole (192.168.30.50). Within Pi-hole i've selected Cloudflare are my DNS provider.

Below is a dig and nslookup from the a client device.

➜  ~ scutil --dns | grep nameserver
  nameserver[0] : 192.168.30.50
  nameserver[0] : 192.168.30.50

➜  ~ dig pi.hole

; <<>> DiG 9.10.6 <<>> pi.hole
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21545
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;pi.hole.			IN	A

;; ANSWER SECTION:
pi.hole.		2	IN	A	192.168.30.50

;; Query time: 2 msec
;; SERVER: 192.168.30.50#53(192.168.30.50)
;; WHEN: Wed Jul 21 22:17:08 EDT 2021
;; MSG SIZE  rcvd: 52

➜  ~ dig www.google.com

; <<>> DiG 9.10.6 <<>> www.google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35212
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.google.com.			IN	A

;; ANSWER SECTION:
www.google.com.		159	IN	A	74.125.138.105
www.google.com.		159	IN	A	74.125.138.99
www.google.com.		159	IN	A	74.125.138.103
www.google.com.		159	IN	A	74.125.138.106
www.google.com.		159	IN	A	74.125.138.147
www.google.com.		159	IN	A	74.125.138.104

;; Query time: 12 msec
;; SERVER: 192.168.30.50#53(192.168.30.50)
;; WHEN: Wed Jul 21 22:17:15 EDT 2021
;; MSG SIZE  rcvd: 139

➜  ~ nslookup www.google.com
Server:		192.168.30.50
Address:	192.168.30.50#53

Non-authoritative answer:
Name:	www.google.com
Address: 74.125.138.104
Name:	www.google.com
Address: 74.125.138.147
Name:	www.google.com
Address: 74.125.138.106
Name:	www.google.com
Address: 74.125.138.103
Name:	www.google.com
Address: 74.125.138.99
Name:	www.google.com
Address: 74.125.138.105

➜  ~ dig pi.hole

; <<>> DiG 9.10.6 <<>> pi.hole
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12914
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;pi.hole.			IN	A

;; ANSWER SECTION:
pi.hole.		2	IN	A	192.168.30.50

;; Query time: 3 msec
;; SERVER: 192.168.30.50#53(192.168.30.50)
;; WHEN: Wed Jul 21 22:29:49 EDT 2021
;; MSG SIZE  rcvd: 52

➜  ~ nslookup pi.hole
Server:		192.168.30.50
Address:	192.168.30.50#53

Name:	pi.hole
Address: 192.168.30.50

jfb · July 22, 2021, 4:40am

Those outputs appear normal.

Coro · July 22, 2021, 7:05am

´

how does this fit together with

?

MKutka · July 22, 2021, 10:53am

Hello,

Appreciate your feedback and I see where in the dig it seems like the query time is normal. I can't explain it, when I update my DNS to either my router or external (1.1.1.1) page times improve significantly to all things (google.com, reddit.com, yahoo.com, etc.) over when i'm running pi-hole as my DNS server. I'll proceed with gathering more digs to other websites after work today.

system · August 12, 2021, 10:54am

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