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.
this post was submitted on 15 Aug 2024
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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.
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)?
Are you running the 2.4 and 5 as separate SSIDs or the same one?
Are you on the latest controller and firmware?
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...
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.
AC Lite. It doesn't need controller, it's standalone. I configure it via the mobile app.
Ah, ok. The Unifi stuff is a bit weird like that. I recommend installing the controller on a computer if you continue to have issues. You don't have to run it all the time, just use it for config and then turning it off is fine. It'll give you way more information and control over exactly how the AP is set up.
I can imagine several causes:
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more than one DHCP server in your network (most likely)
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very wrong DNS setup in your network (unlikely, because I guess you would have given us a hint in that direction)
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heavy downloading traffic and one cheap plastic device (router, switch etc.) runs out of memory
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.
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.
I had a similar issue and it related to the uplink connectivity monitor. Unifi monitors the gateway and controller IP and withdraws the SSID if it can’t contact either of them. Make sure you have turned off wireless meshing on the device and I think you can manually disable the uplink connectivity monitor.
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.
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.
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 |
6 acronyms in this thread; the most compressed thread commented on today has 11 acronyms.
[Thread #922 for this sub, first seen 15th Aug 2024, 07:45] [FAQ] [Full list] [Contact] [Source code]
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.
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.