Repeat Queries from Router (Fritzbox)

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1

The issue I am facing:

After setting up 2 Piholes with keepalived the Main Pihole has every full hour hundreds or thousands of requests from my router. Also im getting the DNSMASQ_WARN warning

Maximum number of concurrent DNS queries reached (max: 150)

2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	29.1 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	36.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	39.8 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	46.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	35.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	42.2 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	46.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	33.4 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	39.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	58.4 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	46.7 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	36.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	32.7 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	51.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	37.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	92.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	44.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	65.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	59.8 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	84.6 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	26.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	27.7 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	29.8 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	25.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	26.5 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	26.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	28.1 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	38.9 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	31.2 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	43.6 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	25.5 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	29.3 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	25.0 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	26.7 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	27.4 µs	
2026-08-06 18:00:50 		A	latest	192-168-178-1.fritz.box	27.4 µs

Details about my system:

RPI4 2gb (backup dns)

RPI3 1gb (main dns)

Both are connected with keepalived and nebulasync.

2

I think that setup is no longer needed now : [RELEASE] Pi-hole HA — automatic DHCP failover, VIP, and config sync for a Pi-hole cluster :grimacing:

3

oh i didnt know! im gonna take a look later

4

Your issue is unlikely to be related to how you keep your Pi-hole machines in sync.

This would suggest that you have configured a DNS loop, where Pi-hole forwards certain DNS requests to your router, and your router sends them back to Pi-hole, which forwards them to your router, and so on.

FritzBox routers can be configured to distribute a local IPv4 DNS server address via DHCP (and to advertise no IPv6 DNS server address at all, or a local IPv6 DNS server address).
When the router propagates your Pi-hole machine as local DNS server, you should refrain from configuring your router to use Pi-hole as its upstream DNS server, see also Fritz!Box (EN) - Pi-hole documentation.