After firmware update, TP-Link Router won't allow local IP in primary DNS field

[knot]

The issue I am facing:
Before I updated the firmware, pi-hole worked well. Since then, router Internet page won't allow any local IP address including my raspberryip as my primary DNS.

Setting primary DNS to pi-hole in router's DHCP server page, only works partially. If I enable the DHCP on pi-hole and disable in router, I can't connect to the wifi anymore.

Anyone encounter this and find a way to get around the webpage validation in the router?

Details about my system:
router still has a permanent IP address to pi-hole.

Screenshots from tp-link forum

What I have changed since installing Pi-hole:

[jfb]

Have you considered downgrading the firmware to the previous version?

[Blockhead]

Have you confirmed that, at the time of the error, your raspberrypi address is what you think it should be?

[Blockhead]

Gulp at the bottom:

Archer A8(US)_V2.28_1.13.2 Build 230824 Download
Published Date: 2023-10-30 Language: Multi-language File Size: 3.81 MB
Modifications:
1.Added support for DoH.
2.Added support for Alexa
3.Added support for HTTPS access.
4.Added IoT network and IoT security.
5.Optimized the guest network, supports Access Time Control and Bandwidth Control.
6.Optimized the easymesh, supports upgrading multiple devices at the same time.
7.Optimized the UI.

Bug Fixed:
1.Fixed several bugs related to IPTV.
2.Fixed several UI bugs.
3.Fixed the bug that the pin doesn't work under certain scenarios.
4.Fixed a compatibility bug with certain intel network cards.
5.Fixed the bug that router can't be accessed remotely via tether.

Note: You will be unable to downgrade to the previous firmware version after updating this firmware.

[knot]

Good point. I also realized I have a repeater, so I unplugged it.

I logged in directly to pi and the wlan0 address is 169.254.xxx.x, which made the router think it's an external address.

• I could put this address in primary DNS.
• Disabled router DHCP
• Enabled pi DHCP
• Devices are shown in pi DHCP leases table, but only my laptop works(without ad blocking). phone disconnects soon after connecting coz "no internet access"

But the blocking isn't working as expected. The only queries shown in pi web interface is NTP requests from localhost.

Dec 22 10:56:53: query[AAAA] 3.debian.pool.ntp.org from 127.0.0.1
Dec 22 10:56:53: forwarded 3.debian.pool.ntp.org to 8.8.8.8
Dec 22 10:56:53: forwarded 3.debian.pool.ntp.org to 8.8.4.4
Dec 22 10:56:54 dnsmasq-dhcp[527]: no address range available for DHCP request via wlan0
Dec 22 10:56:58 dnsmasq-dhcp[527]: no address range available for DHCP request via wlan0

[nprampage]

An address between 169.254.0.0 and 169.254.255.255 means the interface isn't receiving a DHCP-assigned address, i.e. your Pi can't see a DHCP server and doesn't have a static address. So you probably need to figure out why wlan0 can't talk. Setting your primary DNS as this address won't work, pretty sure.

[knot]

Figured out the IP issue, I moved from eth0 to wlan0 interface, but I didn't update /etc/dhcpcd.conf after. Now pihole gets the desired local IP.

I had to updated the primary DNS in internet page. But ad blocking is working as expected in all machines. Thank you!