bluechip wrote

Their response: ... (Please check if you have done some settings on the router page "Advanced > DHCP Server > Address Reservation" ,We can't type in a "space" or " # " in to the "Description bar ",Otherwise ,all the devices can't be detected by the router .It's a bug for the firmware ,and we will release a bate firmware to solve the problem.)

Well, I definitely had address reservations with one or more spaces in the description field. That might explain why it stopped working after a while, because it took me some time to manually enter the address reservations.

Volker

Quetschke,

This is a different but not necessarily unrelated problem. I cannot get a layer 2 connection - it's not therefore DHCP! The subject line is correct for my OP issue.

Mine sometimes does not always detect devices connected via powerline on the device map. Sometimes it detects them as wireless. However, either way, devices have no trouble acquiring and renewing ip addresses.

It would certainly be nice if the interface rejected naming conventions that were not acceptable like it does when attempting to use colons in MAC addresses vs hyphens. Or, at least put that information in the help section accessed by hitting the question mark.

Beta firmware released.
Bug Fixes: DHCP server will be not working when setting DHCP Address Reservation which including specific characters for example a space in the Description box.
http://www.tp-link.com/en/download/Archer-C9_V1.html#Firmware

Beta code works no better for me.

Started with perfectly working 150507 code on 5G. Upgraded to Beta. Added my DHCP bindings, using only strict Alpha characters (just in case).
Rebooted C9 and reconnected at 2.4G. Seemed to work OK for 10 mins.
De-associated and attempted re-connect my PC at 5G - SSID (5G) was there but PC cannot associate with the C9.
Associated at 2.4G, no problem, downgraded code to 150507.
Rebooted C9. Reloaded known working config.bin file. Rebooted. No problem associating with either 2.4G or 5G SSIDs. Both bands working fine after 24 hours.
Conclusion: still something not right in Beta code for 5G.

Are you using mixed modes for the bands?

Almaretto wrote

Are you using mixed modes for the bands?

On 2.4G, it is mixed mode - this works on old & beta firmware.
On 5G it is 802.11ac only - this works on old but not on beta firmware.

I have not yet tried changing the 5G band setup to see if the beta firmware works differently.

Why is this marked as solved? Is that in error?

When I had 5 Ghz network hidden, I would have trouble connecting as well as relatively frequent disconnects. Since I un-hid, my connections have been stable. I have mine on AC/n as my cell phone is the only AC device I own.
For 2.4Ghz, I had trouble with some peripherals like NAS hard drives and printers until I switched it to mixed mode.
I am using DHCP reservations, but no bindings.

That is why I asked. Seems there are obviously some bugs to work out in beta.