Meraki MR AP connection to Catalyst - DHCP Service

[ChannaBasava Kalapurmath]

Hi , New with Meraki , i have question about the DHCP if we are configuring the MR Access Point in Bridge mode.  Clients will obtain the IP address from upstream DHCP Server. 

How the wireless clients broadcast messages reach to DHCP server in other segment  ?? 

which IP used as source by Access Point ? 

Can someone explains the process if the Meraki AP(Bridge Mode) and DHCP server on different subnets. how it works ? 

[Jhosbell Verdesca De Aguiar · Accepted solution]

The DHCP Discover sent by the client doesn't have a source IP, it will be a Layer 2 broadcast that the AP will forward as it is over the VLAN assigned to the client's SSID.

If the DHCP server is not in the same subnet / VLAN than the client, then you need a DHCP Relay to receive that broadcast and forward it to the DHCP Server in unicast.

If the gateway for that VLAN is a cisco router/switch you can make it a DHCP relay agent using the following command: "ip helper address <DHCP Server IP Address>"

[ChannaBasava Kalapurmath]

Thanks Jhosbell..

I was wondering about the Meraki AP behaviour in terms of DHCP requests, if it acts as transparent to L2 broadcast then i'm good. Yes we have relay on the gateway configured which shoud take care of the rest. 

Appreciate your response.