We have several offices across the globe, but our datacenters are primarily housed in two central locations (North America and Europe). There is a relatively high latency between various offices, so we try to host services in the closest location to the user (i.e. Canadian employees use Exchange services in the US, not Europe.)
This setup works well for the most part. When using services like Active Directory, Exchange or DFS, clients rely on existing site information in AD to fine the closest location.
Now, we have a request to have a common DNS name to access certain web services that are hosted both NA and Europe. Previously, we have used seperate DNS names (na-service.domain.local or eu-service.domain.local) but that becomes cumbersome for our end users.
All of our internal DNS is currently hosted on Windows 2003 and 2008 servers with Microsoft DNS. Is there any way to configure Microsoft DNS services to only respond to requests with a "local" IP address? I know that configuring multiple A records will result in a round robin style response, which is not ideal. We could also use Primary zones at each location and only enter the local IP address, but we have hundreds of other DNS entries that would need to be manually replicated to each server.
If this can't be done with MS DNS, are there other low cost alternatives? I know F5 Networks has products that can handle this, but that's at a fairly high expense.
Best Answer
You might have some luck with the "Subnet Prioritization" functionality in the Microsoft DNS server. Whether or not it will help you will depend on how your subnets are addressed and how your geographically "local" servers are addressed. This feature is enabled by default in Windows Server 2003 and 2008.
I'd recommend reading up on that feature. Have a look at http://technet.microsoft.com/en-us/library/dd197495(WS.10).aspx under the "Subnet prioritization" heading.
The "view" functionality in BIND would probably do what you want, too, but then you're talking about deploying a parallel DNS infrastructure and a lot of configuration.
If you have control of the web-based application you could do something off-the-wall like embed some Javascript to "detect" the user's location and redirect them on the client side. It's a bit bush-league, but it might do what you need.