Conflicting DHCP when Deco in AP mode ?
Today I ran into an issue which made me almost cringe.. as I hadn't expect this to happen, considering I've been working in the IT networking business for over 30 years..
I had recently purchased a Deco M5 mesh set with 3 nodes and setup as AP access points, because I alread have a decent router from my ISP (Zyxel EMG2926). This has been working fine for the last 6-8 weeks and nothing to complain about.
Last night, for some strange reason my router rebooted and I lost Internet connexion from everywhere, including my wired PC's which I use every day to work from home.. So getting back internet was critical to me and I tried the quick obvious options like rebooting the router and also reseting to factory the router, then reloading the configuration I had on backup.. To no avail, I wasn't able to get an functional internet, still the router diagnostic was able to ping any IP address outside my network.. Since I needed to work and support clients, I disconnected the Zyxel router and put back the Mercku M2 Hive base I had prior to the ISP router and after 5 minutes, was back into business.. (The Mercku is also a Mesh Wi-Fi system with 4 Bee nodes, albeit it wasn't working to my entire satisfaction, thus the purchase of the Deco M5).
Having spend the morning with work, I had hope the issue with the router might have been on the ISP side, so tried to set it back in action. Result was identical and nothing was really working.. Put the Mercku M2 back for the PM as I had a support call and did need internet ASAP.
At the end of the PM I got back to my router and it was so weird that I even tried to reset the Zyxel for the n-th time and start from scratch.. What puzzled me was that it was working if I forced my computer into fixed IP address, and even with DHCP Mac address reservation, the router wouldn't route my requests properly to the internet.. Looking at the IP addresses in the config made me think that router was totaly corrupt and crazy.. The router's IP is 192.168.127.1, but returns 192.168.127.102 as gateway and .254 for the DNS server, which is even crazier.. This is when I started to scan my network for rogue devices with my Android smartphone, but couldn't find anything suspicious. I've a lot of IoT devices and aside of the 3 Deco M5 AP's, there was nothing un-usual. However, the .102 IP address made me tick and look closer at the Mac Address, to finally discover that the main Deco M5 unit (the one connected by Cat5 cable to the switch) was the culprit.
For some obscure reasons my Zyxel router was thinking that the Deco M5 AP unit was the master DHCP on the network, despite TP-Link saying in their documentation that it is not the case when in AP mode.. As a proof, my Mercku M2 router had no issues at all with that and was perfectly handing over IP addresses to all devices..
Has anyone run into such a situation with another HW router ? getting conflicting DHCP server mode while the Deco M5 is in AP mode ?
I fixed my problem my disconnecting the Cat 5 cable temporarly from the switch, rebooted the Zyxel router and voilà.. after it was back as 'master' DHCP, I plugged the Deco M5 back and all was working as before.. But I'm really curious about that strange behavior.
Any comments are welcome on this.
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It's still a problem with the latest release, although less than it was originally.
My Deco's are in bridge mode.
If I reboot my router the Deco takes over as the DHCP server but at least it maintains the same network.
The problem I have is once I get a DHCP lease on a computers it doesn't release it and that means it doesn't release the Deco as the default gateway.
So for now rebooting the router turns into rebooting the router, and getting some exercise running around the house unplugging the 4 Decos and plugging them back in once the router is back online.
Again, I haven't bothered to put the Deco in Routed mode and see what would happen if I set the DHCP settings to as short as possible.
It would be convienent to be able to completely disable the DR functionality from bridge mode <-- TP-Link please add this feature
Blessings,
Malchambar
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Exact same issue today, first day with a 3-set of Deco X60..
A pure nightmare with the Deco DHCP taking over the main DHCP (on the actual router).
It's totally crazy and irresponsible to do networking like that.
TPLINK >> Please disable completely the DHCP Server of Deco when in AP mode... There is no reason to have your stupid smart dhcp...
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Hmm... It's strange, but I didn't have any DHCP problems with my 3 Decos M4 in AP mode and Mikrotik router with DHCP server running on it. And I have exactly the same configuration as described here: modem -- Mikrotik main router -- 2 M4 Decos, connected directly to router by eth, 1 M4 Deco, connected via TP-Link switch. Tv android box, connected via eth to one of the Deco. A lot of wifi clients. Mikrotik releases a new software version for their router approximately once a month (note, TP-Link), constantly adding something, changing, so I reboot the main router at least once a month. And any described problem with Decos. I have some other issues but not this one ))
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I don't get this type of post, unless of course you post on ALL other threads telling people you don't have the specific problem they are posting. Do you, and if so, why?
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Actually, there is a state when the Deco in AP and a main routeur with DHCP work fine together.
But if either of them goes offline then back up, the deco "smart dhcp" fires up and messes the whole network (2 DHCP servers on the same LAN).
Normally, the Deco being in AP mode shouldn't even try to fire a DHCP server.. That's the issue to solve.
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@phillip_mcmahon simply wanted to say that this is not the problem of all Decos, or maybe ther's no such a problem for the most Decos at least my Decos M4 with the similar configuration and with the similar situation of switching off the main DHCP router, so it doesn't have such type of problem. That's it...
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Gotcha
I think those that haven't experienced this in AP mode are lucky.
Bottom line, it is just a fundamentally broken design feature, un-documented and network destroying when it kicks in. Amazed any network engineer considered this to be a sensible idea and dumbfounded that @tplink still have done nothing about it. How hard is it to provide a way to fully disable this "feature"??
Apologies if I passed my frustration on.
Phill
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Well, glad to see I am not the only one that has this problem.
I ran into it today and it killed my network also. I was able to copy the logs from my Deco W2400 system.
The main issue was it killed my network, second issue is I could not access the Deco via the APP, but could via local web page ( which is useless ). Rebooting my router and disconnecting the deco got my network back up.
Complaints with the system are:
1) No way to configure locally without the damn App. Screwed if you don't have internet access.
2) The local web interface should be able to atleast configure the damn things.
3) Whose idea was it to put a 10/100 only ethernet on it? Capable of more throughput than 100 Mb.
Too bad I can not return them and get something else. I was a fan of TPLink until this.
Kevin_Z, seems like you fell off the face of the net. You running the Deco also?
How about some support?
For as long as this has been an issue, it should have been fixed by now. When I worled for Westel years ago, we NEVER took this long to fix a problem.
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@GPGeek We'll you're definitely not alone. I've dealt with a lot of Deco's, but at one particular house where I've got an M5 network in AP mode and a Virgin Media Hub in Router mode, I have this exact issue (rogue IP addresses being assigned by the Deco's whenever there is a blip on the VM end). Static IP's have been my only viable workaround up to now, but today I'm just going to have to flip the equation so that the Deco's are in Router mode and the VM Router is in Modem mode.
I think that this "Smart DHCP" think might be well intentioned, but it is dysfunctional in its current form.
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