topic Re: New installation - DHCP issues in Wireless

New installation - DHCP issues

Joe Mrazik — Fri, 25 Jul 2025 15:29:57 GMT

We recently deployed MR46 AP's and have discovered a bug on two AP's. Multiple devices could not obtain a DHCP address. The AP's were returned and new ones are good. We are still having devices (iPad) that connect and then at some point no longer connect. Cannot obtain DHCP address or the offer is never sent. By changing the mac address, i.e.- turn on private wifi address it presents a new mac address and sometimes it can connect.

Based on our recent experience with completely failed connections I suspect there is still an outstanding issue. Has anyone else experienced this issue ?

Re: New installation - DHCP issues

mloraditch — Fri, 25 Jul 2025 15:35:07 GMT

What is doing DHCP the AP (NAT Mode) or another device? I've only ever seen anything like this with issues with the DHCP server, not in NAT mode.

Re: New installation - DHCP issues

aleabrahao — Fri, 25 Jul 2025 15:36:29 GMT

What type of authentication are you using and are you using Meraki's DHCP or an external server?

Re: New installation - DHCP issues

Joe Mrazik — Fri, 25 Jul 2025 15:47:07 GMT

DHCP is coming from a Cisco Catalyst switch which is doing ALL of our dhcp wired and wireless. Sometimes we can get this device to work by moving to another AP. We still have a 2504 WLAN controller and seven 3802 AP's, when we move the device within range of that system it connects flawlessly.

Re: New installation - DHCP issues

Joe Mrazik — Fri, 25 Jul 2025 15:50:06 GMT

Authentication is WPA Pre shared key. The most basic auth that will support our users easily.

Re: New installation - DHCP issues

mloraditch — Fri, 25 Jul 2025 16:04:24 GMT

Have you done packet captures or logging on the Catalyst to see if the DHCP requests are coming into the catalyst when things are failing and if so how the catalyst is reacting?

I can foresee two problems that would be the ap, either it's not sending the requests onto the LAN or somehow mistagging them OR the offers are coming back and it's not sending them to the client.

Either way that's the nice thing about DHCP it's plaintext and pretty readable in a capture.

Here's an article that explains the steps: https://documentation.meraki.com/General_Administration/Tools_and_Troubleshooting/Using_Packet_Capture_to_Troubleshoot_Client-side_DHCP_Issues

Re: New installation - DHCP issues

Joe Mrazik — Fri, 25 Jul 2025 16:17:23 GMT

Thanks we will be doing that next. We have an open ticket too.

Re: New installation - DHCP issues

Ryan_Miles — Sat, 26 Jul 2025 01:02:21 GMT

Does it affect all SSIDs or just one of them?

Some general areas I'd look at are the following.

If SSIDs are bridged to a single VLAN don't check the L3 roaming box. That only applies when you have multiple VLANs configured for the SSID. Example, a building with 4 floors and each floor has a unique client VLAN/subnet. L3 roaming could maintain the original IP when devices move between floors.

If you have a single VLAN for the SSID the L3 roaming feature isn't doing anything and could actually lead to issues.

Per best practice I would ensure you have band steering enabled on the SSIDs. You may also look into choosing a smaller channel width for 5GHz (20 or 40 MHz) to allow for more non-overlapping channels.

Check the RRM page AI channel planning section to see if there are any error reports. Sometimes there might be RF jammed or other events occurring.

I would also check the transmit power level of your APs. If many of them are being set to very low/the lowest configured tx power you might have too much AP density & co-channel interference. You can selectively disabled some radios to reduce that issue. You can also use AI-RRM to do this automatically (for the 2.4 GHz radios) . But be aware the free trial of it goes away Aug 1st.

Also, ensure you're running the current stable firmware 31.1.7.1.

And if you don't already have a Support case open I would recommend engaging them. https://documentation.meraki.com/General_Administration/Support/Ways_to_Contact_Meraki_Support

Best of luck and hope you get this resolved.

Re: New installation - DHCP issues

Joe Mrazik — Mon, 11 Aug 2025 18:42:28 GMT

Thanks for all the great input. Discovered we had missed a few vlan settings on distribution switches. Since then, all AP's are reporting normally.

Re: New installation - DHCP issues

Joe Mrazik — Mon, 11 Aug 2025 20:04:41 GMT

Thanks for the Layer 3 roaming tip. Makes alot of sense.

Re: New installation - DHCP issues

Joe Mrazik — Tue, 19 Aug 2025 14:31:38 GMT

Update - one of the MR46's that was working normally started to display the same symptoms.

You see a client with a 0.0.0.0 address, which by itself is not unusual. However after the next refresh cycle the device is no longer visible. It never receives a DHCP address and then usually it is not on the next refresh. Also the number of clients varies wildly from 7 to 38 and then back to 15, or whatever. Totally inaccurate and changes on every refresh. I reopened the ticket and let support capture traces, however they were apparently stumped too. Replacing the AP resolved the issue but I am wondering if anyone else has seen this type of issue.

Re: New installation - DHCP issues

Joe Mrazik — Thu, 04 Sep 2025 18:19:41 GMT

Again, three new MR46's are all doing the same thing. Has been confirmed with a packet capture by Meraki support. "Cisco MerakiCase 13456279: MR 46 not forwarding DHCP to client"

The ISP router does reply with an offer of an IP address, but it is never delivered to the client.

The most frustrating part of this is we have had eight of twenty five MR46's have been RMA'd.

Still no acknowledgment that this is a bug with a specific version of firmware. However I am here to tell you we have been living with this issue since rollout on 7/18/25.

Re: New installation - DHCP issues

Joe Mrazik — Wed, 17 Sep 2025 18:19:29 GMT

Another new AP another issue, same as above. Devices may or may not get an assigned address. Received a new RMA'd AP replacement. Decided to do a burn in test to confirm it is working. Approximately 24 hours after the burn in test began, devices started to display a 0.0.0.0 address.

Some would stay connected and not lose their address yet others would toggle between all zeros and a valid IP address. Contacted Meraki support Cisco MerakiCase 13503579. They confirmed the issue and loaded a beta version of firmware on this single AP. Still in test now. So far it is NOT exhibiting the same issue, however it hasn't been long enough to make sure this doesn't happen again.

Re: New installation - DHCP issues

Joe Mrazik — Wed, 29 Oct 2025 21:48:13 GMT

More of the same DHCP issue. Contacted support again, I must be a regular by now. They did not require me to reproduce this issue. In this case it was just a single SSID. Strangely, if I connect to that SSID from another location in the same building (different AP) it works, and then I roam to this unit and it continues to work. If however you happen to be in this space, no DHCP address is received. I will continue to post here until I see some kind of release notes indicating the problem exists and has been fixed.

Re: New installation - DHCP issues

Joe Mrazik — Wed, 29 Oct 2025 21:50:40 GMT

The beta firmware seems to have corrected this issue. However, it is still loaded with beta firmware. I am expecting a new release at some point.

Re: New installation - DHCP issues

Joe Mrazik — Wed, 04 Feb 2026 15:51:21 GMT

As it turns out this is NOT a DHCP issue at all. The MR46 will periodically display random invalid MAC addresses (i.e.- CB:6F:BF:26:BD:A0) The MAC address does not belong to any registered block, CB:2E:DD:6D:6C:47, C2:E1:98:C0:3B:93 etc. After tracing numerous client devices and confirming they were not the source for this, I can only suspect the MR46. It appears to randomly display these bogus addresses. Ultimately devices start losing connectivity until the AP becomes unavailable. There are clients that stay connected and will work for some period of time. I think the MR46 becomes unusable because of the sheer volume of phantom MAC addresses. My most recent high count was 500 connected devices on a single AP. Meraki support finally admitted this is a known issue and was supposedly corrected with firmware 31.1.8. I have returned more than twelve AP's. The units I receive generally work better. It is hard to determine what the exact trigger event is for this issue but it is NOT RESOLVED. I have been dealing with this for more than six months.

Re: New installation - DHCP issues

Joe Mrazik — Wed, 04 Feb 2026 15:53:12 GMT

This issue IS NOT RESOLVED, FIXED or CORRECTED. Feel free to post if you have experienced this issue.

Re: New installation - DHCP issues

aneduzhk — Wed, 04 Feb 2026 18:08:05 GMT

@Joe Mrazik have you opened a support case? If you have not, please do. If you have, please DM me the case number. Thank you!

Re: New installation - DHCP issues

Joe Mrazik — Wed, 04 Feb 2026 18:36:29 GMT

Thanks, so many cases I lost count. Here is the latest 13844403

Re: New installation - DHCP issues

Joe Mrazik — Thu, 05 Feb 2026 21:20:21 GMT

Update, many thanks to AlexanderN. The timing may be a coincidence, but we finally received the escalation we have been trying to obtain for several months. Advanced logging was captured today along with console developer network tracing by Meraki support.

It finally feels like we are being heard.

Hope to have better news on these updates.