Dual nic and dual public IP on KVM on ovh server

[maudam]

Hi all,
i'm facing an issue with the configuration of a KVM on a server of the provider Ovh.

I'm trying to add a secondary network interface to the same VM but the second ip on the machine remains unreachable.
I added to the vm a second nic (tested with virtio and e1000)

A couple of details:
Ovh give public Ip addresses using a virtual mac address for the interface and using a default gatway with .254 on last octet for routing.
Distro installed in VM is almalinux 9
First interface in guest is ens18
Second interface in guest is ens19

While the first interface is up the second interface is unusable. As soon as i disable the first interface in proxmox gui, the second interface become operative and the traffic pass.
Now the second interface run well but when i enable the first interaface again, this one cannot connect. I have to diable again the second interface and a this point the first interface run again.
It seem that only one interface can be enabled at one time.

Any clue ?

 

[maudam]

An additional info after some test: in a container the dual nic/dual ip function as expected, so this is something about the KVM emulation of proxmox