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  • 1.  Using Aruba Controller for inter-VLAN routing

    Posted Oct 31, 2025 10:59 AM

    Hi,

    I have a question about enabling Inter-VLAN routing on a controller.

    I have 3 VLANs defined on the controller. I am using the controller as DHCP server for these 3 VLANs. Therefore, the controller has an IP within each VLANs 

    I read the documentation, and I understand that controller can act as a Layer-3 switch and forward inter-vlan traffic. The documentation said the controller needs to have an IP address within the VLAN so I have that. My question is on the DHCP front. Do I need to set the controller IP address as the gateway address for each VLAN? Or can I still use my core switch's IP as gateway?

    Thanks for taking a look

    Hanyang



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  • 2.  RE: Using Aruba Controller for inter-VLAN routing

    Posted Oct 31, 2025 11:05 AM

    If you have an existing L3 gateway/router (your core switch, which I suppose is in a small network), I would use that and keep the controller as L2 as possible.

    Clients need to send their traffic to a default gateway, and typically you would use an router/L3-switch for that. If your core switch has an IP in each VLAN and can route traffic; I would do it there. I also would probably put the DHCP on there as well and let the controller switch traffic. In SD-WAN scenarios this is different.

    If your core does not have IP addresses in all VLANs, you could consider configuring those. It would work to route on the controller, but if you have something else that can do it, I would go for external routing.



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    Herman Robers
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    If you have urgent issues, always contact your HPE Aruba Networking partner, distributor, or Aruba TAC Support. Check https://www.arubanetworks.com/support-services/contact-support/ for how to contact HPE Aruba Networking TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or HPE Aruba Networking.

    In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
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  • 3.  RE: Using Aruba Controller for inter-VLAN routing

    Posted Oct 31, 2025 12:34 PM
    Edited by Hanyang Luo Oct 31, 2025 12:36 PM

    Hi Herman,

    Thanks for responding.

    This is a small testing environment for AirGroup and we want to isolate this from our production environment as much as possible. That is why we inclined to do the DHCP and L3 routing on the controller.

    I am inclining to set the gateway address for each VLAN to the controller's IP address. Is that necessary to enable controller to act as the Inter-Vlan forwarder? 

    This is the doc I found online Inter-VLAN Routing. It didn't specify that controller needs to be the gateway to handle Inter-Vlan communication but I wonder if that is the case.

    Thanks for the help again!

    Hanyang

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    Original Message


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