Non-DHCP VLAN Network ARP Problem with OVN

Lazuardi Nasution mrxlazuardin at
Mon Feb 15 00:48:16 UTC 2021

Hi Tony,

On my case, the DHCP port has IP address even I'm not using (disabling)
DHCP on such network/subnet.

Best regards.

On Mon, Feb 15, 2021, 07:45 Tony Liu <tonyliu0592 at> wrote:

> +1
> I asked the same a while ago, didn't get answer.
> When disable DHCP, a port is still created without IP address.
> Not sure what this port is for?
> Thanks!
> Tony
> ________________________________________
> From: Lazuardi Nasution <mrxlazuardin at>
> Sent: February 14, 2021 07:37 AM
> To: openstack-discuss
> Subject: Non-DHCP VLAN Network ARP Problem with OVN
> Hi,
> One of our OpenStack clusters has a VLAN based network without DHCP
> enabled. The cluster uses OVN for SDN.That network has to be like it since
> it will be used for migrating the VMs from other platforms. I have untick
> the DHCP enable feature on creating that network at Horizon. After the
> network and subnet are created, I find that the DHCP port is still created
> even though it is in a down state. I try to delete that port but after some
> time, that port is back again.
> When that DHCP port exists, we find that some VMs inside this OpenStack
> cluster resolve the MAC address of the IP of that disabled DHCP port to the
> MAC address of the DHCP port. The problem is coming since that IP is used
> to an existing VM/server outside this OpenStack cluster at the same VLAN,
> but it only happens for some VMs. Before this finding, I really disregard
> the existence of the DHCP port since it is down and I don't enable the DHCP
> feature. After that, I realize that it is a serious problem.
> My questions are how to completely disable the DHCP feature for such a
> network, including its DHCP port? How can DHCP disabled networks with a
> down DHCP port still respond to the ARP request and why does it happen only
> for some VMs?
> Best regards,
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