I'm trying to set up my IIS server as an origin server for a CDN. I have solved some issues already for example that IIS doesn't give gziped content to proxies (if they have the via header) and also that frequentHitThreshold problem.
My CDN supplier pointed out that another problem with IIS is that it doesn't return a "Vary" header if the client doesn't request the content gziped. According to them the problem is that if for some reason the first client that request the content doesn't want the content gziped the CDN then doesn't request a new version of the file since the Vary header doesn't indicate that it should return two different files depending on "Accept-Encoding".
My only solution so far is to add "Vary: Accept-Encoding" as a custom header but since IIS automatically add this vary header when gziped is requested so i end up with multiple values like "Vary: Accept-Encoding, Accept-Encoding".
Anyone have any solution to this? Or can confirm that it's a real issue.
