ok its uploaded now!!
I sysupgraded from @r00t 's build to yours, DhcpDns. I am having the same issue as
@hyperboarean. Some devices can't obtain ip (wirelessly), others work fine.
My router is behind bridged ISP modem. I only changed wireless network names and passwords. Dhcp and Dns tab is different from the one you shared above, it only shows existing leases (tho it was empty) and no option to set dhcp up.
To be honest Iām not even using open wrt anymore until 4.14 cuz of performance and the latest stock fw work pretty well with nat hardware offload. I tried compiling my own 4.14 for it, if anything thatās what Iām working toward, with your issue you probably just need to disable a dhcp service probably.
Yeah It's probably something stupid on my end.
I see your ddwrt image. Is that a vanilla or patched one?
i didnt know there was a patched version, its just the beta from ddwrt site.the ones that do connect are using fast path though?
I thought you applied some custom patches. How's ddwrt performance? It's been a year since I've last used it.
Heh that's the one thing I didn't test. I have reverted back to @r00t build, but I'll give yours another try today or tomorrow.
No I didnāt apply any patches to ddwrt anyways, Iād use the regular tp link firmware, itās a bit more stable than all of em, plus I donāt think my builds have the fast path or shortcut forwarding engine drivers.
Ok, I'm back to your build. I guess Fast Path is working as I can now max my 500/100mbit line (compared to only reaching 250/100 before), wired ofc.
I've sysupgraded to DhcpDns build (router connected to bridged modem), the only things I've configured are 2.4 and 5ghz wireless networks (different ssid, WPA2 PSK (CCMP)), and enabled upnp. So, here's what works and what doesn't:
Xbox One connects to 5ghz network, upnp works, (I guess 2.4 would work too)
Android tablet (7.1) connects to both
2 W10 PCs work on 2.4, require static IP for 5ghz
2 Android phones (5.0 and custom 8.1 rom) only work with static IPs.
None of this makes any sense to me 
. It seems dhcp only partially works. I also have no idea why PCs only work with 2.4 networks.
I've attached a screenshot of the DHCP and DNS tab. I can also provide you some additional logs, just say which ones will be useful 
UPDATE: after a day I had to set static IP on Xbox and both PCs as well. Only the Android tablet is holding on.
well i just uploaded one with new patches but only the dhcp forward so far, ill try working on whats wrong with the dhcp server.
Well r00t's build is working flawlessly (including the latest one). It's using dnsmasq so that may do the trick. Or more likely something isn't configured properly. I know this build is for you first and foremost so no need to look into that too much 
.
Cool yeah it was mainly meant for dhcp forward, but like I said Iām not using it until 4.14 cuz fast path isnāt cutting it for me.
What does kernel 4.14 bring. Something even better than Fast Path? Also, when is it expected?
Yeah the new 4.14 has hardware nat offload like the original firmware, a bit faster and not stable. The tplink firmware is the fastest in my opinion atm, even wireless is a bit more stable Imo.
This is currently only supported on mt7621 soc... I donĀ“t think support for ar83x7 switch will be added soon...
yes i know, thats what im waiting for buddy.
How do you go about testing local to local bandwidth?
You can do that with iperf3. Unfortunately, you will have to search for instructions yourself as I haven't really done it.
I happen to have a 500/100 connection which I was able to max with online speed tests.
Iperf3 thereās a client/server for windows and linux