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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Give it a rest Kevin.
It's been a problem since 2019, and it is still not fully or consistently removed from your release firmware across the Deco devices. Here you are, still asking for network diagrams.
It's ironic, really, as the "Smart DNS" is a feature meant to help keep a network up for all those dummies who know nothing, yet here we find ourselves in 2024 still requesting network diagrams from people.
Just bin the feature and move on.
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I have found a workaround that works for me.
The problem arises with multiple Deco stations that are wired directly to the modem that acts as a DHCP server.
I purchased a basic 4-port switch, wired my Deco stations (AP Mode) to it, powered everything up, and only THEN connected the switch to the modem. Thanks to the switch, Master en Slave Deco can interact directly with each other as if they were daisy chained (the recommended config) without any interference from the modem. Have not experienced any DHCP issues ever since.
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Ive endured this fault for some years with my Deco M4s but I've finally had enough. Even though the system is configured for Access Point, rather than Router (so that the DHCP server is disabled) they occasionally grab hold of a MAC address and assign another IP address, even if the item is configured for a fixed IP address. Not only is it difficult to analyse what is happening, it is impossible to make the M4s release control. It wastes so much of my time when this happens. I'm a domestic home user, not an IT networking specialist. TP-Link have known about this for years. I'm just going to have to bite the bullet and buy an alternative mesh wi-fi system.
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Hi, I saw you were suggested to install the 1.7.0 beta firmware here which supports turning off "Smart DHCP" under AP mode.
Have you tested the beta firmware already?
Deco M4/S4_V2 Support Connection Preference
Thank you very much and best regards.
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@phillip_mcmahon i have a fix ... sell / return the boxes and buy another brand. Did that years ago and can watch this forum chuntering on with amusement rather than the frustration i felt then. Then again, I did recently buy a TP Link AP and, surpisingly, that's not working very well either. Claimed 365 feet coverage but struggles over 30 feet. My bad for not learning my lesson, I guess.
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@heidarren I just had similar issues with new X95 decos in Access Point mode behind a Cisco RV340 firewall. I had 4 of them, one set up as the main. I set them up in access point mode and dealt with DHCP problems for a week before I removed them. I plugged a laptop in to the wired network. It didn't receive an IP address until I rebooted the decos and my Cisco firewall. I tried to connect a Samsung TV to the wireless network and the same thing happened. No IP address was assigned until I rebooted everything. A also tried several smart devices, like blink camera modules and smart sockets. I ran into the same thing. The set up process failed until I rebooted the decos and firewall. Something is going on with the DHCP server, most likely caused by having two on the same network. I removed the decos, installed 4 unifi Access Points, and no problems now. Wired and wirelss devices get an IP address from my firewall as they should.
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@David-TP In a word, No. This was Beta software and other people had highlighted that it still had issues in AP mode. This was back in February of this year and there was a new formal release of firmware, 1.6.2 back in March. I had assumed that the fault would have been rectified in that release. Surely it wasn't 1.7.0 that you asked me to install as this was only issued as a Beta in March of this year. Looking at the link for this firmare, users are still asking for a formal release of firmware. Are there still inherent issues preventing its formal release?
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Oh, I know. I did that years ago. I'm amazed this is STILL a thing, and official advice is to recommend installing beta firmware almost 6 years after this was first reported.
It's quite an impressive product failure.
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