@ksaro1 

Did you try to change the DNS under the DHCP server to 8.8.8.8/8.8.4.4?

  @Heidi_Alp Sorry, I don't follow? I'm talking about host names on my local network. Remote name servers won't have that information. That should be provided by the Deco. It does list the host names when showing connections. The XE75 does list host names in its Network Map, like shown below:

I currently have one Cloudflare and one of the ISP's DNS server as my DNS servers, which should be shown below:

Oddly, I've found the answer using Google's Bard! Bard tells me that the Deco XE75 does not act as a DNS server. It merely passes all DNS requests on to the primary and/or secondary DNS servers that are defined. You can configure one of your computers on the local network to act as a local DNS server and have the DECO then use that machine as its primary DNS server. However, this then means that that local computer has to have its DNS host/IP list updated whenever any new hosts join and/or leave the local network. Apparently the default update interval is 60 minutes! And there is no way to change this from either the Deco app or the Web interface.

I've just bought 2 Deco XE75s for my home and so far I like a lot of the features and performance. However, not having the Deco XE75 provide any helpful local DNS services is a real drawback and I can't find this mentioned anywhere in any TP-Link or internet literature. 

  @ksaro1 

Sorry, I was delayed by personal stuff last week. As far as I know, Deco is the default LAN DNS server for the devices connected to the Mesh. But it did not support mDNS or local DNS resolution. You are right that Deco merely passes all DNS requests on to the primary and/or secondary DNS servers that are defined. So that's why I suggest you could set up your own Lan DNS server instead of using the LAN IP of Deco---https://www.tp-link.com/en/support/faq/1855/