A few keeners in the crowd recently noticed that although they are waving the red, white and blue, Microsoft Azure has been redirecting them to international instances. And according to a blog by Ganesh Srinivasan, senior program manager for Azure, the reason has to do with a heavy volume of users online vs. a limited number of U.S. IPv4 addresses assigned to Azure.

It seems that Microsoft (MSFT) may be running out of IPv4 addresses in the United States for its Azure cloud services, and Srinivasan wrote in his blog post that the cause may be a lack of IPv4 addresses for American users. But Srinivasan later updated his post to say he had misstated the situation, indicating instead that: "Currently, Microsoft has IPv4 space in U.S. regions. That said, inventory space is a dynamic situation. In the past some customers were assigned non-US IPv4 addresses as a result of limited inventory."

What has been happening is U.S. users have occasionally logged onto Azure to launch a virtual machine, only to have that VM launch in international markets instead. Sometimes that creates some confusion, as the landing pages and information are localized. That doesn't mean the VM is actually being hosted outside of Azure's U.S.-based data centers, but Srinivasan indicated it appears they are. Not exactly reassuring, but at least it's an explanation.

Or is it? Srinivasan later updated the blog to say, "The below blog misstated the situation around Microsoft Azure’s IPv4 address space in U.S. regions. Currently, Microsoft has IPv4 space in U.S. regions. That said, inventory space is a dynamic situation. In the past some customers were assigned non-US IPv4 addresses as a result of limited inventory. We have already updated many major geo-location databases to ensure customers do not experience any confusion in the future. We apologize for any inconvenience this has caused."

That doesn't seem to fully refute the idea that Microsoft is running out of IPv4 address in the United States. It doesn't mean it's going to redirecting more and more IPv4 addresses from other markets, but what it does seem to mean is Azure simply doesn't have enough IPv4 addresses dedicated to the United States to run all the VMs being requested. Most of the time, things are all well, but on occasion, the influx of requests forces Microsoft to grab IPv4 addresses from its other markets.

It seems like good motivation to push toward adopting IPv6. Although Microsoft claims the international IPv4 addresses don't have a negative impact on customers' legal protection around having data and VMs within the United States, but seeing international Azure sites coming up can't be putting American customers at ease.