Updated Ubuntu / Broke Pihole

Blackrock · September 12, 2020, 4:31pm

Expected Behaviour:

Ubuntu 20.04 Server x64
Static Assigned IP

Actual Behaviour:

Updated Ubuntu Server 20.04 which seems to have broke Pihole. It was running just fine yesterday before the updates (was on 20.04 before the package updates as well). Using nslookup and pointing it to the server, nothing resolves, even things that should resolved (e.g. www.google.com). Appreciate any help.

Debug Token:

https://tricorder.pi-hole.net/za74fl4oxa

jfb · September 12, 2020, 4:39pm

You have a connectivity problem on that device:

*** [ DIAGNOSING ]: Networking
[✗] No IPv4 address(es) found on the em1 interface.

[✗] No IPv6 address(es) found on the em1 interface.

[i] Default IPv4 gateway: 192.168.1.1
   * Pinging 192.168.1.1...
[✗] Gateway did not respond. (https://discourse.pi-hole.net/t/why-is-a-default-gateway-important-for-pi-hole/3546)

*** [ DIAGNOSING ]: Setup variables
    BLOCKING_ENABLED=true
    PIHOLE_INTERFACE=em1
    IPV4_ADDRESS=192.168.1.123/24

Blackrock · September 12, 2020, 7:57pm

I can ssh in and ping 8.8.8.8 though.

jfb · September 12, 2020, 8:10pm

From a client that you believe should be connected to the Pi-Hole for DNS, from the command prompt or terminal on that client (and not via ssh or Putty to the Pi), what is the output of

nslookup pi.hole

nslookup pi.hole 192.168.1.123

Blackrock · September 12, 2020, 10:46pm

C:>nslookup rock-media
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 192.168.1.123

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

C:>nslookup rock-media 192.168.1.123
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 192.168.1.123

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

C:>nslookup pi.hole
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 192.168.1.123

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

C:>nslookup pi.hole 192.168.1.123
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: 192.168.1.123

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

C:>ping 192.168.1.123

Pinging 192.168.1.123 with 32 bytes of data:
Reply from 192.168.1.123: bytes=32 time=2ms TTL=64
Reply from 192.168.1.123: bytes=32 time=1ms TTL=64
Reply from 192.168.1.123: bytes=32 time=2ms TTL=64
Reply from 192.168.1.123: bytes=32 time=2ms TTL=64

Blackrock · September 12, 2020, 10:48pm

Netstat on the server...

rock@rock-media:~$ sudo netstat -lnp | grep 53
tcp        0      0 0.0.0.0:53              0.0.0.0:*               LISTEN      850/pihole-FTL
tcp6       0      0 :::53                   :::*                    LISTEN      850/pihole-FTL
udp        0      0 0.0.0.0:53              0.0.0.0:*                           850/pihole-FTL
udp6       0      0 :::53                   :::*                                850/pihole-FTL

jfb · September 12, 2020, 11:15pm

Check your Pi and router for any port 53 firewalls or redirects that are interfering with port 53 traffic.

Blackrock · September 13, 2020, 12:14am

No firewall rules on router nor any iptables rules on my server

Current connections as per my ASUS router... (these are Google devices hardcoded to use Google DNS all other devices fall back to the router as the DNS server should the pihole be down)
udp 192.168.1.242:35660 8.8.8.8:53 ASSURED
udp 192.168.1.147:54198 8.8.8.8:53 ASSURED
udp 192.168.1.147:32969 8.8.8.8:53 ASSURED
udp 192.168.1.102:51983 8.8.8.8:53 ASSURED
udp 192.168.1.64:45384 8.8.8.8:53 ASSURED
udp 192.168.1.147:40166 8.8.8.8:53 ASSURED
udp 192.168.1.102:35194 8.8.8.8:53 ASSURED
udp 192.168.1.147:49322 8.8.8.8:53 ASSURED
udp 192.168.1.64:54050 8.8.8.8:53 ASSURED
udp 192.168.1.242:50255 8.8.8.8:53 ASSURED
udp 192.168.1.64:50624 8.8.8.8:53 ASSURED
udp 192.168.1.242:47579 8.8.8.8:53 ASSURED
udp 192.168.1.102:45623 8.8.8.8:53 ASSURED

PCAP ran on my server hosting pihole

rock@rock-media:~$ sudo tcpdump -n -t -r ~/dns.pcap port 53
reading from file /home/rock/dns.pcap, link-type EN10MB (Ethernet)
IP 192.168.1.32.35695 > 192.168.1.123.53: 51120+ A? scribe.logs.roku.com. (38)
IP 192.168.1.32.44514 > 192.168.1.123.53: 47508+ A? www.googleadservices.com. (42)
IP 192.168.1.32.36415 > 192.168.1.123.53: 38845+ A? r6---sn-qxoedn7d.googlevideo.com. (50)
IP 192.168.1.200.40611 > 192.168.1.123.53: 24007+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.40611 > 192.168.1.123.53: 35698+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.49027 > 192.168.1.123.53: 9450+ A? checkip.dyndns.org. (36)
IP 192.168.1.200.54395 > 192.168.1.123.53: 57993+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.54395 > 192.168.1.123.53: 35047+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.32.35207 > 192.168.1.123.53: 38597+ A? r4---sn-q4flrnez.googlevideo.com. (50)
IP 192.168.1.32.57898 > 192.168.1.123.53: 32644+ A? scribe.logs.roku.com. (38)
IP 192.168.1.31.51308 > 192.168.1.123.53: 25948+ A? 6c50b6bb6ac861983c454ea1bef9b60b.clo.footprintdns.com. (71)
IP 192.168.1.200.49027 > 192.168.1.123.53: 9450+ A? checkip.dyndns.org. (36)
IP 192.168.1.200.54395 > 192.168.1.123.53: 35047+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.13.36462 > 192.168.1.123.53: 28305+ A? connectivitycheck.gstatic.com. (47)
IP 192.168.1.13.36462 > 192.168.1.123.53: 25585+ AAAA? connectivitycheck.gstatic.com. (47)
IP 192.168.1.200.40611 > 192.168.1.123.53: 24007+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.32.36988 > 192.168.1.123.53: 31639+ A? scribe.logs.roku.com. (38)
IP 192.168.1.200.54395 > 192.168.1.123.53: 57993+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.40611 > 192.168.1.123.53: 35698+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.49027 > 192.168.1.123.53: 9450+ A? checkip.dyndns.org. (36)
IP 192.168.1.31.51312 > 192.168.1.123.53: 1+ PTR? 123.1.168.192.in-addr.arpa. (44)
IP 192.168.1.13.35432 > 192.168.1.123.53: 64031+ A? connectivitycheck.gstatic.com. (47)
IP 192.168.1.13.35432 > 192.168.1.123.53: 55645+ AAAA? connectivitycheck.gstatic.com. (47)
IP 192.168.1.31.52184 > 192.168.1.123.53: 47806+ A? google.com. (28)
IP 192.168.1.200.58202 > 192.168.1.123.53: 23464+ AAAA? checkipv6.synology.com. (40)
IP 192.168.1.31.60769 > 192.168.1.123.53: 49700+ A? clients6.google.com. (37)
IP 192.168.1.200.58524 > 192.168.1.123.53: 44075+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.58524 > 192.168.1.123.53: 52174+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.32.59093 > 192.168.1.123.53: 29986+ A? scribe.logs.roku.com. (38)
IP 192.168.1.31.60771 > 192.168.1.123.53: 2+ A? www.google.com. (32)
IP 192.168.1.200.58524 > 192.168.1.123.53: 52174+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.31.60772 > 192.168.1.123.53: 3+ AAAA? www.google.com. (32)
IP 192.168.1.200.58524 > 192.168.1.123.53: 44075+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.58202 > 192.168.1.123.53: 23464+ AAAA? checkipv6.synology.com. (40)
IP 192.168.1.31.63319 > 192.168.1.123.53: 53444+ A? router.asus.com. (33)
IP 192.168.1.31.63320 > 192.168.1.123.53: 4+ A? www.google.com. (32)
IP 192.168.1.32.34128 > 192.168.1.123.53: 40225+ A? scribe.logs.roku.com. (38)
IP 192.168.1.32.48250 > 192.168.1.123.53: 15491+ A? scribe.logs.roku.com. (38)
IP 192.168.1.31.63321 > 192.168.1.123.53: 5+ AAAA? www.google.com. (32)
IP 192.168.1.31.55265 > 192.168.1.123.53: 47090+ A? graph.facebook.com. (36)
IP 192.168.1.200.58202 > 192.168.1.123.53: 23464+ AAAA? checkipv6.synology.com. (40)
IP 192.168.1.200.58524 > 192.168.1.123.53: 52174+ AAAA? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.58524 > 192.168.1.123.53: 44075+ A? checkipv6.quickconnect.to. (43)
IP 192.168.1.200.58202 > 192.168.1.123.53: 23464+ AAAA? checkipv6.synology.com. (40)

Blackrock · September 13, 2020, 1:42am

So I may have found the issue. Looks like one of the updates cause my LAN interface to be renamed to eth0. I made the change in one of the pihole config files, but it didn't fix it. I then backed up the configuration via teleporter, reinstalled pihole, and then restored my block and whitelists. Pihole is now working again.

system · October 4, 2020, 1:42am

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