Conditional Forwarding cannot be saved (validation error)

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1

Hi Team,
Been a while since my last posting here.
I am not sure if I have come across a bug or perhaps I done something wrong.
I’m seeing what looks like a small issue with Conditional Forwarding in Pi‑hole v6.

On two separate Pi‑hole v6 installations [Core v6.4.2, FTL v6.6.2, Web interface v6.5]
(two Raspberry Pi 4B devices), trying to enable Conditional Forwarding always fails with this message:

Config item validation failed
dns.revServers[0]: <enabled> not a boolean ("192.168.2.0/24")

I’m only entering the usual three fields:
Local network: 192.168.2.0/24
Router IP: 192.168.2.1
Local domain: HanLop

The UI accepts the values, but clicking Save & Apply always gives the same validation error on both systems.
The config files look normal and nothing seems corrupted, so it might be the UI not sending the “enabled = true” flag.

Everything else works perfectly — just wanted to report it in case it’s helpful.

Thanks and whish you a great Sunday!

warm regards - Steen

2

You're forgetting the first out of four fields/components named enabled:

Allowed values are: Array of reverse servers each one in the following form:

"<enabled>,<ip-address>[/<prefix-len>],<server>[#<port>][,<domain>]"

Explanation of individual components:

  • "<enabled>": either "true" or "false"
  • "<ip-address>[/<prefix-len>]": Address range for the reverse server feature in CIDR notation. If the prefix length is omitted, either 32 (IPv4) or 128 (IPv6) are substituted (exact address match). This is almost certainly not what you want here. Example: "192.168.0.0/24" for the range 192.168.0.1 - 192.168.0.255
  • "<server>[#<port>]": Target server to be used for the reverse server feature Example: "192.168.0.1#53"
  • "<domain>": Domain used for the reverse server feature (e.g., "fritz.box") Example: "fritz.box"

Eg:

true,192.168.2.0/24,192.168.2.1,HanLop

3

Hi deHakkelaar,

Ahhh crap — one must read the documentation properly after all :grinning_face_with_smiling_eyes:
With your input I realised the UI wasn’t assembling the full revServers string.

I used the CLI instead and Conditional Forwarding now works on both Pi‑hole instances.

I applied:

sudo pihole-FTL --config dns.revServers '[ "true,192.168.2.0/24,192.168.2.1,HanLop" ]'

Then verified that the TOML file was updated correctly and that PTR lookups resolve as expected.
Everything is working now — thanks for pointing me in the right direction.

Thanks for the great work!

Warm regards - Steen