Account for simple url rewriting in ASP.NET MVC redirect

How would you go about redirecting in ASP.NET MVC to take into account some external URL rewriting rules.

For example:

• What the 开发者_StackOverflow社区user enters: http://www.example.com/app/route
• What ASP.NET MVC sees: /route
• What I want to redirect to: http://www.example.com/app/other_route
• What actually happens when I do a simple RedirectToAction: http://www.example.com/other_route (which doesn't exist, from the outside anyway)

This seems like it should be simple, but I'm drawing a blank.

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Just use

RedirectToAction("NewAction", "Controller-Required-If-Diferent-From-Current-Controller");