Fresh install Pi-Hole working just fine, suddenly it stops working

Help
1

The issue I am facing:

Hi, I'm using Pi-hole 5.1.2, at fresh install, and OpenDNS Family Shield as DNS Servers. Everything was working pretty good, but just hours later it stops blocking ads, OpenDNS Family Shield stop working also at the same time. DNS queries are being processed and forwarded.

Details about my system:

Raspberry pi lite 5.4.51-v7

Pi-Hole 5.1.2, FTL - 5.2, AdminLTE 5.1.1

Working interface = Raspberry pi Ethernet 0

Static Ip address.

What I have changed since installing Pi-hole:

Nothing, working just fine for hours after a fresh install and suddenly stops doing it. Traffic DNS forwarding but OpenDNS Family Shield doesn't work also, that's weird.

2

Please generate a debug token with pihole -d or via web interface.

3

Hi, yes of course: https://tricorder.pi-hole.net/as85fclqrm.

4

A moderator will have a look when time permits.

5

Are you clients actually set up to use Pi-hole as their sole DNS server, or is your router handing out a secondary address, too? Primary and secondary DNS rarely works the way people expect it to, usually the request is sent to both, and the response that comes back first is the one that is used, rather than "in case of primary failure, use secondary"

6

Hi PromoFaux, yes actually I use Pi-hole as my sole DNS.

Not sure what is happening, I think pi-hole is forwarding all traffic through my local ISP DNS Servers, but I'm not sure how it learned them. I configured FamilyShield Ipv4 DNS Server and OpenDNS IPv6 in my pi-hole.

This is pi-hole resolv.conf:

# Generated by resolvconf
nameserver 208.67.222.123 - FamilyShield
nameserver 208.67.220.123 - FamilyShield
nameserver 2800:200:2000::410 - ISP IPv6 DNS server (somehow, auto-learned from ISP)
nameserver 2800:200:2000::d0 - ISP IPv6 DNS Server  (somehow, auto-learned from ISP)
nameserver 2800:200:2000::c7 - ISP IPv6 DNS Server  (somehow, auto-learned from ISP)

I disable every DHCP Server (IPv6 and IPv4) in my router, even IPV6 and in my client (Windows10), it just talks in IPv4.

Quite weird, I'm taking another Debug report: https://tricorder.pi-hole.net/6vjvjvc3mz

P.D. Also, I see this config in my device:

:~ $ cat /etc/resolvconf.conf 
# Configuration for resolvconf(8)
# See resolvconf.conf(5) for details

resolv_conf=/etc/resolv.conf
# If you run a local name server, you should uncomment the below line and
# configure your subscribers configuration files below.
#name_servers=127.0.0.1

# Mirror the Debian package defaults for the below resolvers
# so that resolvconf integrates seemlessly.
dnsmasq_resolv=/var/run/dnsmasq/resolv.conf
pdnsd_conf=/etc/pdnsd.conf
unbound_conf=/var/cache/unbound/resolvconf_resolvers.conf

:~ $ cat /var/run/dnsmasq/resolv.conf
# Generated by resolvconf
nameserver 208.67.222.123
nameserver 208.67.220.123
nameserver 2800:200:2000::410
nameserver 2800:200:2000::d0
nameserver 2800:200:2000::c7

pi@pi-hole:~ $cat /etc/pdnsd.conf
cat: /etc/pdnsd.conf: No such file or directory

:~ $cat /var/cache/unbound/resolvconf_resolvers.conf
# Generated by resolvconf

forward-zone:
        name: "."
        forward-addr: 208.67.222.123
        forward-addr: 208.67.220.123
        forward-addr: 2800:200:2000::410
        forward-addr: 2800:200:2000::d0
        forward-addr: 2800:200:2000::c7
7

From debug log:

    PIHOLE_DNS_1=2620:119:35::35
    PIHOLE_DNS_2=2620:119:53::53
    PIHOLE_DNS_3=208.67.222.123
    PIHOLE_DNS_4=208.67.220.123

Pi-hole will only be using those servers as upstream, it does not use the nameservers in resolv.conf (unless I'm very wrong here, but I don't think so!)

The rest is going to be down to IPv6 configuration. It is likely that your router is handing out your ISP's v6 nameservers to your clients, and they are querying those. Though, I'm afraid I'm not much help here... I tried to start understanding IPv6 a few years ago, and I ended up having so many issues just trying to get my head around it, that I just disabled it at the router level... Personally I can't see that I'm missing out on anything by doing so.

8

Oh! so, I'll disable all IPv6 configuration in my network and ISP Router, then I'll do some tests.

I'll let you know if doing that solves this issue.

9

Hi PromoFaux, I tried to disable all IPv6 settings in my router, all clients are working with IPv4 but doing a NSlookup I got this:

#nslookup google.com
Server: pihole
Address: 192.168.10.2 (IPhole LAN IP address)

Non-authoritative answer:
Name: google.com
Addresses: 2607:f8b0:4008:813::200e
142.250.64.142

I think my local ISP is forwarding somewhere else with IPv6.

So, I think this is it, thanks so much for your help this time. Hope, I'd solve this in the future.

10

If you are concerned about the Ipv6 address showing up here: DNS is agnostic about the protocol used. This means even when querying via Ipv4, the answers can contain both ipv4 and ipv6 address of the domain. But if your local clients do not have a ipv6 route to the internet, the can't reach that address.

11

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