Unifi AP behind an extra switch: 2.4Ghz network stops working after ~30 minutes

Submitted ⁨⁨2⁩ ⁨months⁩ ago⁩ by ⁨sylverstream@lemmy.nz⁩ to ⁨selfhosted@lemmy.world⁩

I have a very weird issue. I’ve got a relatively simple network setup:

router connected to ONT (Fibre)
10 port switch A connected to router, cables to various places in house
4 port switch B connected to switch A, with TV & Xbox connected
Unify WiFi AP connected to switch A, both 2.4Ghz and 5Ghz networks

That works well. However, when I connect the WiFi AP to switch B I’m having issues. Initially it all works well, but after ~30 minutes the wifi stops working; I can no longer ping e.g. the router. It only happens to one of the WiFi networks (2.4Ghz or 5Ghz), not both. A reboot of the AP solves it again, but then it stops working after ~30 minutes.

Both switch A and B are 1Ghz switches, zero issues with other devices.

Any idea what I can try?

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just_another_person@lemmy.world ⁨2⁩ ⁨months⁩ ago
Double check the AP doesn’t have a DHCP server enabled. Also, check routes and IP settings when a client first connects to the AP and things work, then again when things stop working.

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- sylverstream@lemmy.nz ⁨2⁩ ⁨months⁩ ago
  Yep, thanks for checking, there’s only 1 DHCP server on my network. I’ve just moved it back to behind switch B and will do more investigation when the problem occurs again.
  
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fhqwgads@possumpat.io ⁨2⁩ ⁨months⁩ ago
Do you have a continuously running unifi controller or is it only running when you do the config? Does it do the same thing with the controller opposite to how it is now (ie if you aren’t running it does it do it when you leave the controller on)?

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- sylverstream@lemmy.nz ⁨2⁩ ⁨months⁩ ago
  It’s a standalone AP. No controller. Two different SSIDs.
  
  I’ve had it running now for 2 hours and of course now it works. The only change since last time is that I’ve reset the AP and did a firmware upgrade. Perhaps that fixed it…
  
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  - fhqwgads@possumpat.io ⁨2⁩ ⁨months⁩ ago
    Which model is it? As far as I’m aware all the Unifi APs need the controller for config. It doesn’t need to stay running unless you want a couple features for large deployments but you do need to run it to set things up initially. The Air Max / uisp lines are the ones with web based config.
    
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NeoNachtwaechter@lemmy.world ⁨2⁩ ⁨months⁩ ago
I can imagine several causes:

more than one DHCP server in your network (most likely)

very wrong DNS setup in your network (unlikely, because I guess you would have given us a hint in that direction)

heavy downloading traffic and one cheap plastic device (router, switch etc.) runs out of memory
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- sylverstream@lemmy.nz ⁨2⁩ ⁨months⁩ ago
  There’s only a single DHCP server, a Pihole, which also serves as DNS. Switch B is a cheaper switch, so that may be the culprit. I use it for heavy downloading from my Xbox and that is never a big issue. Speeds fluctuate from 100 to 900mbps (my max) but that’s not necessarily a switch problem.
  
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  - NeoNachtwaechter@lemmy.world ⁨2⁩ ⁨months⁩ ago
    Measure the time after the reboot of the AP until the next failure.
    
    If it is always the same duration, then that excludes the memory problem. If it is a variable time, then that excludes the DHCP problem and probably also DNS.
    
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SpazOut@lemmy.world ⁨2⁩ ⁨months⁩ ago
I had a similar issue and it related to the uplink connectivity monitor. Unifi monitors the gateway and controller IP and withdraws the SSID. Make sure you have turned of wireless meshing on the device and I think you can manually disable the uplink connectivity monitor.

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Decronym@lemmy.decronym.xyz ⁨2⁩ ⁨months⁩ ago

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:

Fewer Letters	More Letters
AP	WiFi Access Point
DHCP	Dynamic Host Configuration Protocol, automates assignment of IPs when connecting to a network
DNS	Domain Name Service/System
IP	Internet Protocol
PoE	Power over Ethernet
Unifi	Ubiquiti WiFi hardware brand

[Thread #922 for this sub, first seen 15th Aug 2024, 07:45] [FAQ] [Full list] [Contact] [Source code]

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jake_jake_jake_@lemmy.world ⁨2⁩ ⁨months⁩ ago
from your router can you ping the AP behind that switch, while the issue is occurring? All L2 unmanaged switches, no tagging? POE from the switch or an injector? If from the switch maybe put an injector in between?

I work for an ISP in the network engineering dept, I personally have never seen an issue exactly like this before, but we generally do power calculations for switching and wifi, this sounds like a power issue to me.

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- sylverstream@lemmy.nz ⁨2⁩ ⁨months⁩ ago
  I’ve just moved it back to behind switch B, will do testing as you suggest.
  
  The switch doesn’t have POE, the Unifi AP does use POE via its own POE injector.
  
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teslasaur@lemmy.world ⁨2⁩ ⁨months⁩ ago
Reset the AP to make sure it uses dhcp for its own ip and update firmware from unifi network after adopting the AP again.

Test it by swapping places of the access points to find out if the issue is related to the access points or something else.

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- sylverstream@lemmy.nz ⁨2⁩ ⁨months⁩ ago
  Thanks. I’ve recently reset it, it has its own IP via DHCP. I’ve just moved it back to behind switch B, will do testing as you suggest.
  
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