IIS sc-win32-status 64 when using url rewrite over https and ColdFusion

Question

I've run into a very specific and annoying problem. It involves all of the following:

• Windows Server 2016 (IIS 10)
• Url Rewrite Module
• ColdFusion 2016
• https

When a rewrite rule is triggered to point to a ColdFusion (.cfm) page, the page seems to return fine in most browsers, but in Firefox it shows no status code in Developer Tools, and in Safari 9.1 (not in Safari 8 or 10!?) the page won't load at all. This happens only if all of the following are true:

• It's a ColdFusion page (doesn't happen with a .txt or .aspx file)
• The url is rewritten with the URL Rewrite module (e.g. /test1 rewritten to /test1.cfm)
• It is over https

When I look at the request in the IIS logs, what I see depends on the browser. It looks normal when I access with Chrome. With Firefox, it shows two requests, the first with a sc-win32-status of 64 and the second with 0. With Safari 9.1 (where the page won't load at all) it shows repeated requests, mostly with sc-win32-status=64, but also some with 22 and 1168.

Any help appreciated.

Answer 1

After digging and digging, I found that this is a known issue related to IIS10 and http/2. Both Adobe and Microsoft got involved and Microsoft should be releasing a fix in April 2018. A short term fix is to disable http/2. Our hosting provider also suggested installing the BonCode connector as a fix.

Note that this does not just affect url rewrite, but also default document settings.

https://tracker.adobe.com/#/view/CF-4198446

UPDATE: This is fixed as part of KB4093120

https://support.microsoft.com/en-us/help/4093120/windows-10-update-kb4093120