I am working on an azure hosted multi-tenant web application. Azure will provision a VIP address on initial cloud service deployment. The VIP address will not change for the lifetime of the deployment. I will have hundreds to thousands of domains setting up A-records to our multi-tenant application (VIP address).

What I am afraid of somehow losing the VIP. That is a HUGE risk. This would be catastrophic in that hundreds or thousands of customers' sites would be down as they would have to change their A-records/CNAME's to the new VIP address.

I'd like to find a way to buy an IP address and use that IP address as a proxy to the VIP so that if the VIP changed (bad things), then I could simply change the proxy to point to the new VIP. How would one do this?

  • 1
    If you don't trust Microsoft, you shouldn't host on Azure. That said, if they did change people's IPs on them, they wouldn't be in business for very long, would they?
    – MDMarra
    Jul 14, 2013 at 18:39
  • It's not that I don't trust Microsoft. Someday we may want to create a new deployment or whatever and we lose the VIP. I wanted to see if there was a way of adding a proxy layer so I could make 1 change to point to the new IP so customers don't have to change as well. Jul 14, 2013 at 19:37

2 Answers 2


As all your customers are just pointing an A record to "your" IP address, why not setup an A record in your DNS list customers.company.com and just have all your customers point a CNAME from whatever.them.com to customers.company.com. This way if you ever decide to leave Azure and go to another hosting site your customers don't need to change anything. As soon as their DNS cache expires they'll be pointed to your new IP.

That said, the risk of Microsoft changing that IP address on you is basically zero. Just like any other hosting provider they can't go around changing public IP addresses on people.

  • 1
    I thought of doing this, however A-records only accept IP address entries (at least GoDaddy is like this). So in order for naked domain routing of my customers to our hosting, they have to setup their A-Records to point to our Azure VIP. Jul 14, 2013 at 19:40
  • Correct A records only accept an IP Address. CNAME records point to other DNS records such as A records. The client CNAME of something.client.com points to your A record customer.company.com. Customer.company.com points to an IP address. When the DNS lookup for something.client.com happens it finds customer.company.com and returns the IP address for customer.company.com.
    – mrdenny
    Jul 15, 2013 at 7:04
  • This is not meant to be an advert as I have no affiliation with them apart from being a happy customer, but dnsmadeeasy.com have something called ANAME records. Basically it's an A record as far as the client is concerned but their server does the lookup behind the scenes for whatever host you want it to resolve to Oct 10, 2013 at 20:56

You can get a static IP address assigned to you by pretty much any ISP, in much the same way you got one from microsoft azure, but you'll have to trust the provider not to change it just the same (and most will reserve the right to change it with notice to you).

ARIN (or your local RIR) will not typically assign /30 subnets for this purpose because it complicates routing and is inefficient, and in any case you would need to arrange for routing on any block assigned to you, which is not a trivial task.

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