Duplicate Clients Reappearing in “Known Clients” After Removal

Help
1

I’m seeing around 25 clients listed under Clients > Add a New Client > Known Clients that are already manually configured. When I try to re-add one of these, I get the error:

Failed to add client xxxxx – Already present

If I remove the duplicates that are already configured, I can re-add them successfully — but after a reboot or a few days, the same duplicates reappear.

Setup Notes:

  • I manually manage IP addresses and client names using /etc/hosts. I’ve done this since v3.
  • I do not use Pi-hole as a DHCP server — IPs and hostnames are managed via the UniFi Console.
  • This issue began after upgrading to the latest core versions.

System Info:

  • Pi-hole Core: v6.1
  • FTL: v6.2
  • Platform: Raspberry Pi 4

Debug Token:

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

2

I've been seeing this as well. The new "known clients" are returned from https://github.com/pi-hole/FTL/blob/88737f6248cd3df3202eed72aeec89b9fb572631/src/api/network.c#L341; in my case the pihole-FTL network table has some entries where hwaddr is not lowercase, so the match to existing clients in gravity.db fails.

I was able to repair the database with

pihole-FTL sqlite3 /etc/pihole/pihole-FTL.db "update network set hwaddr = lower(hwaddr)"

No idea what caused the network entries to get added in uppercase.

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