[swiftcoder]

> If you control the target URL it is easy, just redirect back. Seriously: The browser won't loop

Just uh... don't do this if you have a CDN infront of your site. We had an incident where Cloudfront cached the 301's in both directions

[geocar]

Yeah that's a good point, but one way to think about a CDN is like a web browser that you control, so I say do it even with a CDN and remember you can always just flush the "browser" cache! (or in cloudfront's case: create an invalidation and wait a few seconds)