Meraki Wireless DHCP success rate vs multiple DHCP servers

[Jaganmohan]

Hi,

In a network with multiple DHCP servers configured in Load Sharing mode for a single SSID, where a client's DHCP REQUEST reaches both servers but only one responds while the other rejects the client's IP request, will Meraki flag the server which didn't respond to this request as a "no DHCP response" and reflect the same in the Wireless Overview -->  Network service health --> DHCP Success?

Is there a Meraki document with explanation of how the Meraki dashboard tracks the DHCP success rate for clients in such a scenario?

Thanks

Jagan

[alemabrahao]

Similar to RADIUS success, Dashboard will be able to capture the failures happening around the DHCP server as well. Dashboard will have a very similar categorization of all the clients that can successfully get a DHCP IP address from the server and any failure that occurred for any client device. We capture reason codes in case the client was not able to get a DHCP IP address from the server. These can be found in the Server RCA documentation. 

As with all other tiles, Dashboard will be filtering out for most APs and clients failing for DHCP. A network administrator can quickly jump to a specific AP and/or client just by clicking on the device name.

Network Service Health - Cisco Meraki Documentation

[Jaganmohan]

Thanks for the quick reply and the documentation. I have gone through it, but what I don't understand is the scenario where we've more than one DHCP servers in load balance mode in the network.

How do Meraki dashboard process the client DHCP request sent to 2 servers and only receive one response from one DHCP server.

[RaphaelL]

That's a good question , but are you sure that only 1 DHCP server is responding ? Usually they should all respond and the client will accept the first proposal received.

[PhilipDAth · Accepted solution]

>where a client's DHCP REQUEST reaches both servers but only one responds while the other rejects the client's IP request,

This should be a failure event.  Both DHCP servers should be responding if they are load-sharing.  The client should send a DHCPNAK back to the second DHCP server, declining its address offer.

[Purroy]

In addition to that, which is entirely correct, each DHCP request has a transaction ID which is included in the replies by the servers (however many different servers reply). So, it is really easy for MRs/Dashboard to follow the whole DHCP process even when getting replies from diff servers.