Lost ARP Announcement Packet for Meraki MR30H Access Point

[yldrmali]

Hi,

I have a setup with following  components.
* Cisco - Meraki MSS120-8FP Gigabit Ethernet Switch
* Cisco - Meraki MR30H Access Point (POE)
* GRMS Device with LwIp Stack
* 2 PC with Windows 10.
* My PC (Windows) to ping


When I try to ping the GRMS device through MS120-8FP everything works perfect. Diagram is like below.
My Pc -> MSS120-8FP -> GRMS Device ---- Ping works perfect.

However, if I try to connect through Access Point, it fails.
My Pc -> MSS120-8FP -> MR30H -> GRMS Device ---- Ping fails.

The problem seems to be related to the ARP table. When the MR30H is powered on, devices connected through the LAN detect it. My GRMS device then sends an ARP announcement ( We have also observed this behavior with IP devices from other manufacturers). I would normally expect the MR30H to update its ARP table upon receiving this packet, but it doesn't. It disregards the packet. After approximately two minutes, the device becomes truly active and starts accepting incoming ARP announcement requests. If the GRMS device is connected directly to  MSS120-8FP, this problem is not observed.

As a temporary fix (hotfix), I configured my GRMS device to send ARP announcement packets every 10 seconds for 10 minutes. This resolves the issue, but this behavior is not standard practice.

If I connect two Windows 10 PCs to the MR30H and try to ping each other, it succeeds after the MR30H finishes initializing. This is because Windows PCs periodically send ARP announcement packets.

Is there a permanent solution to this problem besides my current hotfix?

[marce1000]

 - You may post that in https://community.meraki.com/t5/Switching/bd-p/switching
    and or                     https://community.meraki.com/t5/Wireless/bd-p/wireless-lan

 M.

[Kumaresan Ravichandran]

• Verify that the MR30H is correctly configured to operate in bridge mode or access point mode, depending on your network topology.
• Some network devices support ARP inspection features that can help mitigate ARP-related issues. Check if the MR30H access point or the MSS120-8FP switch supports ARP inspection or similar ARP security features, and configure them appropriately.
• Consider alternative network topologies that may bypass the MR30H access point or utilize different network equipment to connect devices. For example, you could connect the GRMS device directly to the MSS120-8FP switch if feasible.
• If no other solution is available, you may need to continue using your current hotfix script to periodically send ARP announcement packets from the GRMS device. However, this is not an ideal solution and should only be used as a temporary workaround until a permanent solution is found.
• If you can't handle it. Just reach out to Cisco Meraki support for assistance with troubleshooting the ARP handling issue on the MR30H access point. They may be able to provide additional guidance or escalate the issue to their engineering team for further investigation.

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