Having on-prem IP to point to Azure VM

Question

I have a case where I want to migrate on-prem servers to Azure, but I should still have the local IPs pointing to these VMs. I mean by the local IPs the country-range of IPs since these VMs should be accessed using country IPs for regulatory reasons.

I heard that this is possible, but I have no idea what type of resources I should use to allow this, VNET, VPN, ExpressRoute ?? And how to do it as I have no experience in networking what so ever.

Regards,

Answer 1

NAT is a method of remapping one IP address space into another by modifying network address information in Internet Protocol (IP) datagram packet headers while they are in transit across a traffic routing device.
You can setup a site-to-site VPN between on-prem and Azure Vnet, then deploy a server on-prem run as the NAT device.

Answer 2

It is possible, but with some complications and constraints:

1. You can run these servers/VMs in Azure using their public IP addresses. You need to create the Virtual Network using these address ranges, but it is possible. The catch here is that these public IP addresses are only accessible via cross premises connectivity solutions such as Azure VPN gateway or Azure ExpressRoute. You cannon access these VMs using their "public" IP addresses directly over the Internet. For this purpose, these public IP address ranges are really treated as "private addresses".

2. Once you create the virtual network with the public IP addresses (as private address space) in Azure, you will also need to make sure your routing in the on premises network is configured correctly to forward the traffic to these VMs over the VPN tunnels or MPLS/WAN network if you are using ExpressRoute.

3. If these servers/VMs need to accept requests directly from the Internet, the traffic from the Internet will still come to your on premises network because that's where your ISPs will direct the traffic. You will need to ensure these traffic will be routed correctly over the cross premises connectivity (VPN/ExpressRoute) to Azure.

Hope this helps a bit. Please let me know if this answers your question.

Thanks,

Yushun [MSFT]