New with iOS 9 and Mac OS X 10.11 is ATS, App Transport Security. To help you troubleshoot HTTPS settings, Apple is providing a command line tool called nsurl.

As I’m using a Self-Signed certificate, nscurl fails for me with all its settings. Something like this:

---
TLSv1.2 with PFS disabled
2015-10-06 18:11:59.609 nscurl[39559:5040069] CFNetwork SSLHandshake failed (-9801)
2015-10-06 18:11:59.610 nscurl[39559:5040069] NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9801)
Result : FAIL
---

As far as I could find, there’s no parameter to specify a certificate to be used. The only work-around I was able to use is:

  1. Install the certificate on your Mac’s keychain.
  2. Using Keychain Access, change the trust settings of the certificate to “Always Allow”.

With this change you should be able to run nscurl and see the results. Please remember to remove the certificate from your keychain afterwards.