I'm trying to setup a VPN connection from a VLAN in Azure to on-premise. We have two different ISP's on-premise and I want to setup Azure with a VPN connecting to both so that if the primary ISP is down Azure will try to connect using the secondary.
The problem is that I can't add two gateways to a single VLAN, and the one gateway will not let me add two VPN connection with the same IP address range. I can understand that if I wanted both to be active, but I want one to be standby and only used if the first disconnects.
Is this even possible? Any pointers would be great?
I have been looking at https://learn.microsoft.com/en-us/azure/vpn-gateway/vpn-gateway-highlyavailable#a-name--activeactiveonpremamultiple-on-premises-vpn-devices but that only covers active-active setup which is not what I want.
I want both VNET resouces and on-premise resources to reach each other via the same IP addresses no matter if it's the primary or secondary VPN that's connected.
I know that Azure has fail over on it's side via a standby gateway, but I want fail over when on-premise is down, not Azure.