I have an IIS site with NTLM and sitespeed.io, run via Docker, seems to be unable to get past the NTLM Part.
I'm very new to sitespeed.io but have searched their documentation and found nothing to say it does, or does not, specifically support NTLM.
The script I have been running on a Windows 10 machine is:
docker run --rm -v "%cd%":/sitespeed.io sitespeedio/sitespeed.io http://intranet.company.com/Pages/default.aspx#/
The configuration docs indicate that only Basic auth is supported, and this issue comment confirms that NTLM is not supported. (Generally, I'd assume that if something's docs don't affirmatively say the tool supports NTLM auth, it probably doesn't support NTLM.)
You'll need to disable auth entirely, enable Basic auth on IIS, or route your requests through a NTLM proxy (which is not ideal since it necessarily affacts the timings you're trying to measure).