I recently updgraded to version 6 but....
When I run a UDP dns query the remote server times out. (dig cbs.nl)
When I use tcp it is ok. (dig +tcp cbs.nl)
This means that my phone cannot use the pi-hole as a dns server.
dig should result in an IP response
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The problem looks like it is external to Pi-hole, you can see that the status is Forwarded and the logs show that the upstreams are not responding to UDP.
2025-04-17 14:32:53.618 CEST [1764/T1792] ERROR: Cannot receive UDP DNS reply: Timeout - no response from upstream DNS server
2025-04-17 14:32:53.619 CEST [1764/T1792] INFO: Tried to resolve PTR "1.1.1.1.in-addr.arpa" on 127.0.0.1#53 (UDP)
2025-04-17 14:32:55.699 CEST [1764/T1792] ERROR: Cannot receive UDP DNS reply: Timeout - no response from upstream DNS server
2025-04-17 14:32:55.699 CEST [1764/T1792] INFO: Tried to resolve PTR "8.8.8.8.in-addr.arpa" on 127.0.0.1#53 (UDP)
2025-04-17 14:32:57.778 CEST [1764/T1792] ERROR: Cannot receive UDP DNS reply: Timeout - no response from upstream DNS server
2025-04-17 14:32:57.779 CEST [1764/T1792] INFO: Tried to resolve PTR "4.4.8.8.in-addr.arpa" on 127.0.0.1#53 (UDP)
The upstreams are configured to be:
Apr 17 14:32:49 dnsmasq[1764]: using nameserver 8.8.8.8#53
Apr 17 14:32:49 dnsmasq[1764]: using nameserver 1.1.1.1#53
Can you run your dig commands again but set the upstreams as the DNS server instead of Pi-hole? dig cbs.nl @8.8.8.8 and dig +tcp cbs.nl @8.8.8.8.
Also that does not work over udp.
Delta.nl maybe blocking the UDP 53 port?
But something has changed in pihole as it was working before the upgrade to 6.
Is there a way to downgrade?
DNS uses udp by default, it only escalates to tcp when the packets are too big. Almost all of the DNS traffic is going to be udp.
If you can not resolve dig cbs.nl @8.8.8.8 using udp then it's not Pi-hole that is broken, it's your network. No sane ISP is going to block UDP 53.
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