@herwig 

That's a common issue for double NAT network. If you make your Modem as a pure modem them no issue on this thing.

But yes I also agree there could be some improvement on the router page, like a warning or suggestion

EDIT

  @Somnus thx for the info.

It is really weird that by default the ip address of the gateway is published to the clients and the gateway does not run a DNS Server.

Forwarding the ip of the upstream DNS would be a solution for most cases, however if you want to have multiple WANs, there is no way around a local DNS Server.

Using the router as a "Switch" is no option either -> in this case, there is no need for the router at all...

It is strange that this basic functionality is not managed by tp-link as this is a vital feature which all - even the cheapest routers - provide ...

What I also find confusing is that I watched a lot of setup videos before selecting omada and I do not remember that this issue has ever been addressed ...

I guess the most vise setup would be to have a raspberry with Pihole and the omada controller running ... -> would be cheaper than the OC200 and support the "special" functionality of having a local DNS server

really strange move from tp-link ...

this is not the easy setup that I expected ...

  @btx thx for your answer.

I totally agree, it is a shame that such a vital functionality does not even not run out of the box but that it is not even mentionied that there is a problem.

concerning the auto dns in LAN:

This is the case that I use. In this case, the devices receive the ip-address of the gateway as dns-server -> which is very strange as there is - as you mention - no dns server running ... -> does not look like a professional solution to me!

Using the router as a switch does not make any sense as this would eliminate the whole failover and routing functionality - which is one of the main reasons for this architecture.

very disappointed ...

EDIT

  @btx 

to be honest, I still believe that I miss something - such basic functions should work out of the box ... specially for a company with networking knowledge and capabilities like TP-link

their consumer products do support all these features. There is absolutely no reason why the business devices have less capabilities!

EDIT

My solution:

I run the omada controller on a vps - nothing fancy is required (in my case I have a local vps with 2CPUs, 2GB Ram and 10GB HDD).

The omada controller is installed as a docker instance.

In addition to the omada controller, I also run a pihole with the docker-compose file as described here: https://hub.docker.com/r/pihole/pihole

I configured the primary DNS to be the ip of my omada controller (which is also the pihole). The secondary DNS Server is configured to be the one from cloudflair.

So far this setup works good ... no problem so far.

regards

  Herwig

 @Somnus 

@btx 

I got suggestions for further testings ... What I figured out is that if you set 1.1.1.1 and 8.8.8.8 as DNS-Servers for the WAN interface, also the LANs (which are set to DNS auto) work without a problem - the router does forward the DNS requests correctly - as it should!!

In my case, after the test as described earlier, I set the WAN DNS-Server to the IP of the standard gateway from the WAN interface (which was also provided by DHCP) which is connected to the WAN interface of the omada router. -> this worked as well ...

After this test, I deleted the (optional) DNS-Setting from the WAN interface -> which defaulted back to the IP of the upstream gateway again -> and also this setting worked now!!!

There seams to be a software bug that in some cases, this setting works and in other cases, it does not ... -> I hope a developer will find this thread to solve the problem in near future!

Suggested workaround if you encounter the issue that DNS seams not to work:

1. set the WAN DNS-Server to static IP addresses e.g. 1.1.1.1 or 8.8.8.8 (or both) -> apply changes and verify if they work

2. remove these (optional) settings -> apply changes and verify if this works ...