Deco M9 Plus in AP mode taking over DHCP server and assigning IPs in own subnet
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After installing the M9 in access-mode in my network, I notice some devices cannot be reached anymore.
When examining the situation I notice that the IP the devices get is in the range the M9 uses when in router mode.
When switching to Router-mode, the (internal)M9 IP is: 192.168.78.1 and the DHCP range it uses is from 192.168.78.100 to 192.168.78.200 with a subnet of 255.255.255.0.
Router mode is unusable in my situation, so I'm forced to use the AP-mode.
Some devices (like a "Wemos D1" board, a Thermostat and sometimes my printer when turning it on) get an IP in the 192.168.78.x range while my
cable-modem (Lan Gateway with IP: 192.168.178.1 and subnet 255.255.255.0) is setup to handle the DHCP with a range of 192.168.178.30 - 192.168.178.250 .
The weird thing is that the cable-modem is UP all the time when one of these devices is added, but still doesn't get an IP from my Modem and because of the
different subnet, can't see the device. The device says it's up and running on the SSID from the Deco M9, with the Deco M9 given IP.
From within the Deco App, the device can be seen WITH the wrong IP address....
Because the devices it happened to are headless and no monitor can be attached, looking at the network from the device is not possible.
For some reason the Deco M9 DOES listen AND responds to DHCP requests in certain situations,
making networking a real challenge, even for someone with a good background in networking!
I hope someone will fix this serious flaw in the firmware...
I'm not the only one experiencing problems with DHCP in AP-Mode accordig to several other posters on the community.
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As far as DHCPD goes IIRC the DCHP client starts renewing its lease at the half way point of expiration.
I've also observed that the only way to wrest control of DHCPD from the Deco to the Router is by reloading the Deco(s).
I think that's because the renewals requests are sent to the Deco IP addresse and any new device coming online that sends a BOOTP broadcast for a DHCP address gets waylayed by the Deco (it has to transit the Deco to get to the Routers DHCP server). The Deco ends up answering the new request, so the "real" DHCP server doesn't get to be heard by the Deco (in smart DHCP mode) and the Deco doesn't give up control.
In theory, I can see the logic behind the smart DHCP in a home network. It should make local devices accessible when the Internet is down. Unfortunately, it has the above mentioned side affect which makes it a nightmare when put into practical application.
(I'm a networker not a programmer, but I bet this is called an infinite while loop, because the condition to stop behaving as a DHCP server is never attained on the network.)
I have considered putting my Deco back in routed mode and adjusting the DHCP scope to match my router's scope... but I haven't taken the time to schedule a maintenence window with the rest of the family.
I've also considered putting it back in routing mode and putting everything behind the Deco, I just haven't brought myself to reconfigure the whole network because of a errant feature.
Blessings,
Martin
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Sadly this is just more working around the rather silly choice of TP-Link of not allowing a simple to implement, complete shut down of their DHCP service.
I don't care if they think their device connectivity is more important than the rest of my network.
@Kevin_Z it is a no brainer. Give us the check box to turn this off please.
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@Malchambar @MDec @phillip_mcmahon
Hi, sorry to respond late due to the Chinese Mid-Autumn festival.
I do understand your request to turn off the DHCP server forever, but we are sorry to tell you that this option is not available yet; and the smart DHCP is designed to handle the network system when the main router's DHCP server failed.
For this feature, we have noted that and our engineer will evaluate the feasibility to add it; For this case, I ask for your kindly waiting and patience. It will take some time before releasing a new feature.
Back to the original concern, per you know we do receive some reports that the Deco in AP mode will take over the DHCP server randomly, but compared to the large amount of Deco users, the current issue is rare;
However, we do value you customers' feedback, we have tried to do some tests at our lab but no avail, the Deco in AP mode will turn on DHCP server automatically when it detected that the main DHCP server fall down, in the same time, once it detects there is another DHCP server existed, the smart DHCP will turn it off.
So to locate the issue and find out a solution, it will be much appreciated if you can provide the information we need. Including the network diagram, model number of the main router, and the packets between them.
Thanks for your support and cooperation in advance.
Best regards.
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@Kevin_Z I can assure you it is not rare! As I have bought and installed many decos and had the unfortunate fun to explain this intorelable behaviour in 4/10 networks last week. I also use these in work and have found the same. When somebody does not take the time to write it here, it does not mean, that the problem is not there. We have some basic principles in networking and this is simply irresponsible. Please give us the feature to disable this asap!
Marek
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Hey Kevin, I don't think what we are asking for is understood. This should not be a case of your engineers spending/wasting time on individual cases, but using that time to provide people with the option to FULLY disable the DHCP server feature. Nothing more complex than that.
Throwing up an unwanted DHCP server, that uses a different scope for addresses simply causes chaos on a network. I think anyone working with networks can understand this and it shouldn't require further technical debate.
Why the resistance to providing this simple option?
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Can you share whether the option to fully disable DHCP is accepted in the product roadmap and when we are likely to see this in a public, or even beta, release.
Appreciate your support in getting the product where it needs to be.
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Can someone tell me if this problem get solved in near future? It's really annoying. the dhcp server is not offline and nevertheless, the deco takes over.Even it it would be possible to configure or disable this feature could help to solve. At leased swich the dhcp server to an other setting bings the deco back until the next take over.
Using the deco as router is not an option since is ha not enouth features.
I hope it will be fixed as soon as possible witzh the next firmware update.
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Kevin - any chance of an update?
Just knowing whether this will be addressed or not in a future firmware would be of great help.
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We have been wating for two months now Kevin...
As said, this is deeply irresponsible from your engineers, aswell as TP-Link itself.
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Due to a restart and maintenance with my DHCP service the TP Link's in AP mode decided to ruin my network and toss out IP addresses to devices in a different range, YET AGAIN.
Kevin / Support / SOMEONE - please help your customers here and offer the option to FULLY disable ALL DHCP services when in AP mode.
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