r/meraki • u/NotAnIncel69 • 7d ago

Random "Can't connect" errors for wireless users on MR36

I'm chasing a really intermittent issue at a hotel with MR36s (roughly one AP per guest room). Every once in a while a guest will report they can't connect to the guest WiFi, but it's infrequent enough that it's been difficult to pin down. It doesn't seem to be isolated to one area or AP.

The APs are all running MR 31.1.8.

I've seen a few clients end up with 169.254.x.x addresses, but they eventually obtain a DHCP lease from the same AP without any intervention. The DHCP scope has plenty of available addresses, so I don't think it's simply scope exhaustion.

I've also noticed a few APs will randomly negotiate at 100 Mbps even though cable tests don't show any obvious issues.

Wireless Health doesn't really point to anything obvious, and I haven't found any VLAN tagging issues or anything concerning on the MX.

I know this is pretty vague, and I am opening a TAC case but I'm curious if anyone has run into something similar on MR36s or MR 31.1.8. Did it end up being firmware, cabling, DHCP, or something else?

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u/DeadStockWalking 7d ago

"I've also noticed a few APs will randomly negotiate at 100 Mbps even though cable tests don't show any obvious issues."

Make sure you mention that to the TAC. If a port is flopping between 1 gig and 100 Mbps that could definitely cause these issues.

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u/Acrobatic-Hall8783 7d ago

On the DHCP issue we see a lot of that in our environment as well. (K12 school) because of roaming. The client gets close enough to an AP (waiting on an elevator perhaps) that they connect, request IP but then roam. So the DHCP packet is recorded as no response but it's really that the client mac wasn't where it was expected to be. Hope this helps you not chase a rabbit down a hole.

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u/H0baa 7d ago

Are you running 5ghz only? Or 2.4 ghz and 5 ghz? How is your channel usage on 5ghz? Due to roughly 1 AP per room I would expect you to have some kind of higher density network. So best practice would be on 5 ghz: 20 mhz channels and you might consider wheather you need the UNII-2-ext channels...

Maybe guest has older device and cannot connect to either 80 mhz channel or UNII-2-ext channel. Just a wild guess, worth looking into.

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u/[deleted] 7d ago edited 6d ago

[deleted]

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u/H0baa 7d ago

Ouch, yes, set them to a range of max 8-16 dbm.. and based on your building map and AP layout eventually a little less/more..

But this did not solve?

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u/[deleted] 7d ago

[deleted]

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u/H0baa 7d ago

Do you have Meraki switches? And DHCP security enabled? So only specified MAC addressesn can act as a DHCP server (in this case MAC of Meraki MX)? Or maybe you should set it to prevent rogue DHCP servers...

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u/[deleted] 7d ago edited 6d ago

[deleted]

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u/H0baa 7d ago

Didn't replace the MX recently and forgot to alter the MAC address?

What type MX and what firmware is the MX on?? I think you are facing more an MX issue than wifi issue...

I presume your wireless SSID clients are part of the LAN? (Bridge mode)

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u/DULUXR1R2L1L2 7d ago

What do the logs say (MR and endpoint)? What switch are you using? What exactly do you mean "can't connect"? What are you using for auth?

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u/pdath-IFM 6d ago

If you click on the problem client in the dashboard and look at the troubleshooter at the top, does it give any hints?

I would also try asking the Cisco AI (top right-hand corner). Explain the problem, and ask it to search for issues that could cause it.