Forum Discussion
Using ASR to Migrate servers to the same subnet
We have already extended our on premise data centre to the Azure cloud and it is working really well, so good that we want to migrate some of our exsisting on prem servers to in the cloud. For a few of the legacy applications we want to kepp the IP's and hostnames, of these on prem servers. Just wondering what best practise in failing servers over into an Azure network with the same subnet as your on prem infrastructure.
2 Replies
I'm afraid Eric is right...
You won't be able to use the same subnet (layer 2 connectivity) natively with Azure, even with ExpressRoute for example, without the help of some third party solution.
Another way you could look at this is to redesign the network architecture around the application that requires the same IP.
Depending on how clients connects to the app, you could for example create a new address space with the same ip subnet in Azure, but not connect it back to your on-premises network and instead get the client to access the application through a public endpoint. I realise there are many factors to be considered such as performance, security, etc. but this is only an example to get you thinking about different approaches to the problem if you can't get the layer 2 connectivity going in Azure.
Cheers,
Stephane
I believe you'll need a network appliance like Cisco CSR to extend/stretch your onpremise subnet into Azure. I don't think you can natively extend your onpremise subnet into Azure without it.
