request.url is returning internal hostname...

Hi all,
 
I'm using request.url to retrieve the URL of the current request. However, in my production environment, while behind a load balancer, request.url is returning the internal hostname of the request.
For example:
http://www.myserver.com/Page.aspx is being return as http://internalservername/Page.aspx
I thought request.url gets the path name from the request submitted by the user's brower? Shouldn't request.url in that case return the external URL?
Any clarification would be great.
Thanks!
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