Yes I am both surprised and disappointed that this fundamental feature is missed out on ER7212PC, which is supposed to be a business-grade product. 

I wonder what take the team so long to push in this change to it. 

It is doing DNS Proxy - it issues its own IP address as the DNS server for DHCP clients so it is accepting DNS requests and passing them on to the upstream DNS servers. 

However there is no config and no support for DNS over HTTPS or DNS over TLS - so you can't do secured Cloudflare Zero Trust DNS filtering through it currently.  Would be great to see this feature added at some point - just the same as it is for the standalone ER routers.

I'm not very impressed with the ER7212PC after deploying it at a site I manage.  Not only is the configurable DNS Proxy feature missing, but when I left it set to issue its own address as the DNS server for DHCP clients (set DNS server to Auto under the DHCP settings for a LAN), I found it frequently stops responding to DNS queries altogether so users experience being disconnected from the internet.  Setting it to issue external DNS servers via DHCP does not seem to be a problem.  It looks like the DNS functionality on this device is not up to scratch.

  @dunxd Thanks for explaining why I’ve been experiencing more internet outages since adding the ER7212PC to my network. I tried setting up a custom DNS server to check if my ISP was having issues and was surprised to find that Omada actually supports a DNS Proxy feature. This feature would let me route all DNS requests over DoH to an Adguard Home instance.

However, I couldn’t find the ‘DNS Proxy’ tab on the ER7212PC interface, and now I understand why it’s missing … strange decision to leave that out.

To address the issue you mentioned, should I override the DNS settings under ‘Internet’ or ‘LAN’? At least I can set it to use Cloudflare or Google DNS.

  @Bitshifter The ER7212PC looks to be lagging behind the features of the other routers. I dont know if this is because it is resource constrained - it is running the functions of an OC200 as well as routing - or TP-Link haven't made all the functions available yet for some other reason. Perhaps they can answer. It would be really good to make this work.

The DNS settings in the Internet section are those used by the router itself should it need to contact the internet for updates, cloud management etc. The DNS settings in the LAN section are those to be used by other devices on the LAN - i.e. set these to allow your devices to do their own DNS requests directly.