The controller by default acts as a layer 2 device. The controller will follow the switching rules and forwards BUM traffic to the upstream network. If a DHCP response is received from an external DHCP server the response is forwarded to the client. There is no additional config on the controller needed for this.
It is possible that the controller acts as the DHCP server for a WLAN network but most deployments while use an external DHCP server.
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Willem Bargeman
Systems Engineer Aruba
ACEX #125
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Original Message:
Sent: Feb 25, 2025 01:16 PM
From: Armin
Subject: Controller and DHCP requests
Hi, wondering if someone could explain to me the data flows for DHCP, in tunnel forwarding mode, and how a controller deals with the requests?
When a user that connects to WiFi gets authenticated and is assigned a role, the controller maps that role to a VLAN. Next the user tries to get an IP, therefore it will send a DHCP discovery message, and this message gets tunnelled to the controller. From the upstream layer 3 device, I can see SVI with DHCP relay config for my VLAN, so I can only assume the controller bridges the DHCP frames to the upstream wired network rather act as a relay or proxy itself, but whereabouts on the controller I can see these settings for my WLAN?
Thanks