I have recently started a fresh v6 install on a fresh bookworm image.
Pihole installation seems to go just fine, and I'm manually assigning the pihole as DNS server to some of my devices. As soon as I save those details, no connections go through.
Actual Behaviour:
Here's what the pihole query log shows: https://imgur.com/XNkQu1h Update: I've changed this cloudflare and there's no change in behavior.
I've tried changing between various DNS providers but it doesn't change the result: "No reply received".
, where it also says there's no response from the upstream DNS server.
There was also a brief moment of hope when I found this thread (https://www.reddit.com/r/pihole/comments/1islibw/ntp_error_after_pihole_v6_update/) as I thought an NTP error was causing issues; my router is set for US west coast time manually, so I thought the pihole trying to force a different time was the issue. However, unchecking ntp.ipv4.active and the other settings didn't fix it.
Any help to get this back up and running would be appreciated. I think my situation may be similar to what is described here: DNS does not resolve for UDP - #3 by petergeelhoed
but I'm not sure what I should try to resolve any potential network issues should this round of pihole debugging not succeed.
Your debug log shows Pi-hole to be operational, but it cannot communicate with public DNS servers:
*** [ DIAGNOSING ]: Name resolution (IPv4) using a random blocked domain and a known ad-serving domain
[âś“] www.olx.pl-oferta2320592.shop is NOERROR on lo (127.0.0.1)
[âś“] www.olx.pl-oferta2320592.shop is NOERROR on eth0 (192.168.1.86)
[âś—] Failed to resolve doubleclick.com via a remote, public DNS server (8.8.8.8)
Run from your Pi-hole machine, please share the output of:
I went ahead and tried a different workaround: booting up a different PC with a brand new Ubuntu install, then installing pi-hole. No difference in result, I'm still getting no response from the upstream DNS server.
Part of me thinks it's my router but it worked just fine with my pi-hole back on V5, making me think it's something there.
$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host noprefixroute
valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether c8:60:00:70:1e:db brd ff:ff:ff:ff:ff:ff
inet 192.168.1.85/24 brd 192.168.1.255 scope global dynamic noprefixroute enp2s0
valid_lft 34312sec preferred_lft 34312sec
inet6 fe80::6e18:c8bc:2bd4:f862/64 scope link noprefixroute
valid_lft forever preferred_lft forever
$ ip route
default via 192.168.1.254 dev enp2s0 proto dhcp src 192.168.1.85 metric 100
192.168.1.0/24 dev enp2s0 proto kernel scope link src 192.168.1.85 metric 100
That’s…. Interesting? The addresses is set as static on the router for the Ubuntu machine that pihole is on. I just went into the wired connection settings on Ubuntu and set it as manual there with the same address and right now it’s not reconnecting to the internet.
$ sudo netplan generate
$ sudo netplan try
systemd-networkd is not running, output might be incomplete.
Failed to reload network settings: Unit dbus-org.freedesktop.network1.service not found.
Falling back to a hard restart of systemd-networkd.service
Do you want to keep these settings?
Press ENTER before the timeout to accept the new configuration
Changes will revert in 111 seconds
Configuration accepted.
~$ ip route
default via 192.168.1.254 dev enp2s0 proto dhcp src 192.168.1.85 metric 100
192.168.1.0/24 dev enp2s0 proto kernel scope link src 192.168.1.85 metric 100
Immediately after I did that, the pi-hole gave me this error: 2025-07-14 21:51:01 CONNECTION_ERROR Connection error (**1.1.1.1#53**): failed to send UDP request (**Network unreachable**)
I changed the contents of the netplan as suggested but have the same results as above.
$ sudo nano /etc/netplan/01-network-manager-all.yaml
$ sudo netplan generate
** (generate:136831): WARNING **: 18:09:30.577: Permissions for /etc/netplan/01-network-manager-all.yaml are too open. Netplan configuration should NOT be accessible by others.
goyo@goyo-pihole:~$ sudo netplan try
** (process:136980): WARNING **: 18:09:34.017: Permissions for /etc/netplan/01-network-manager-all.yaml are too open. Netplan configuration should NOT be accessible by others.
** (generate:136982): WARNING **: 18:09:34.025: Permissions for /etc/netplan/01-network-manager-all.yaml are too open. Netplan configuration should NOT be accessible by others.
** (process:136980): WARNING **: 18:09:34.842: Permissions for /etc/netplan/01-network-manager-all.yaml are too open. Netplan configuration should NOT be accessible by others.
** (process:136980): WARNING **: 18:09:34.984: Permissions for /etc/netplan/01-network-manager-all.yaml are too open. Netplan configuration should NOT be accessible by others.
Do you want to keep these settings?
Press ENTER before the timeout to accept the new configuration
Changes will revert in 118 seconds
Configuration accepted.
$ ip route
default via 192.168.1.254 dev enp2s0 proto dhcp src 192.168.1.85 metric 100
192.168.1.0/24 dev enp2s0 proto kernel scope link src 192.168.1.85 metric 100
Same pihole error in the FTL log too: 2025-07-15 18:09:34.976 WARNING Connection error (1.1.1.1#53): failed to send UDP request (Network unreachable)
Yes, this is a fresh ubuntu install. I've added steam to it but have yet to do anything else. For reference, I ran into the original problem with a Raspberry Pi 1B+, tried switching to an Ubuntu install on a different desktop.
And yes, 192.168.1.254 is the router.
$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=118 time=4.46 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=118 time=6.11 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=118 time=4.80 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=118 time=3.45 ms
64 bytes from 8.8.8.8: icmp_seq=5 ttl=118 time=4.20 ms
^C
--- 8.8.8.8 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4005ms
rtt min/avg/max/mdev = 3.446/4.604/6.113/0.876 ms