UPDATE (June 13, 2014)
The below blog misstated the situation around Microsoft Azure’s IPv4 address space in US regions. Currently, Microsoft has IPv4 space in US 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.
Some Azure customers may have noticed that for a VM deployed in a US region, when they launch a localized page on a web browser it may redirect them to an international site. The following explains why this may be happening.
IPv4 address space has been fully assigned in the United States, meaning there is no additional IPv4 address space available. This requires Microsoft to use the IPv4 address space available to us globally for the addressing of new services. The result is that we will have to use IPv4 address space assigned to a non-US region to address services which may be in a US region. It is not possible to transfer registration because the IP space is allocated to the registration authorities by Internet Assigned Numbers Authority.
At times your service may appear to be hosted in a non-US location.
Service and Data are located where deployed
It is important to note that the IP address registration authority does not equate to IP address physical location (i.e., you can have an IP address registered in Brazil but allocated to a device or service physically located in Virginia). Thus when you deploy to a U.S. region, your service is still hosted in U.S. and your customer data will remain in the U.S. as detailed in our Trust Center: http://www.windowsazure.com/en-us/support/trust-center/privacy/
We are currently working with a few major IP geo-location database companies to update the location of these IPs which should help alleviate the issues this may be causing.