@Alex. At firmware 1.5.5, Deco M9plus has a "Smart" DHCP which sometimes messes my network even in AP mode. In my case, I have Deco M5, firmware 1.6.0 which allow to disable this feature,so I've promoted one of M5 to main Deco. My network is very stable now. 

@Alex. 

If you plan to run Deco M9 Plus in Router mode, here is the answer from TP-Link Support: https://community.tp-link.com/en/home/forum/topic/207382

Hi @TP-Link !

I have my own DHCP-server, and would like to assign certain IP ranges to certain devices. 

Kind regards,

Alex.

Alex. wrote

Hi @TP-Link !

 

I have my own DHCP-server, and would like to assign certain IP ranges to certain devices. 

 

@Alex. 

What you described is standard functionality of DHCP server. Deco also has it, take a look at How to configure Address Reservation with Deco?

You will have to use Deco DHCP server instead of yours, and this will also require you to set IP address reservation in Deco for each of your devices you want to have static IP address assigned to, but it is one time undertaking. 

If this is too much work or does not work for you for any reason, I would suggest you look for WiFi mesh from different brand. It is very unlikely an option to disable DHCP in Deco Router mode will appear for Deco M9 any time soon. The feature list for next M9 firmware does not include it, and that next firmware might be months before GA.

This is still broken as I have a functional DHCP server in my network and "Smart" DHCP refuses to remain disabled.  It is causing my network to be practically unusable because it keeps stepping over my real DHCP server.  For this product to be useable for those of us who run a real DHCP server (there's a ton of us, clearly) this feature needs to have an option to completely disable.  I don't want it to ever come on unless I turn it on, why is that such an impossible concept for the developers to grasp??  Just let me turn it off, and while you're at it, let me set whatever WiFi channel that I want to use!  I paid $500 for a WiFi system that I expect to be able to use.  It is unusable.  That price point comes with a certain expectation of control, and the power users currently have zero control.  

I have two x90's at the latest firmware in AP mode.  Just want DHCP disabled indefinitely and the ability to select my WiFi channels.  My DHCP server is serving a limited scope of IP's to my network, leaving about half of the range for static IP's.  I suspect perhaps this is why "Smart" DHCP is failing at its job.  Maybe it doesn't play well with limited DHCP scopes in the environment?  Whatever the case, the correct resolution would be to remove the "smart" feature and just leave it off if the user turns it off.  It really is maddening!!