Install IIS agent4 and enable post-data-preservation mode. Submit POST data to protected resource.
- POST data is submitted onto the protected resource, browser returns 200 status.
- browser reports 404 error. Agent log shows this message:
2018-06-27 10:31:16.195 +0200 DEBUG [3236:2416][source/process.c:2691] handle_exit(): replaying preserved data (d32c7847-9895-ff48-ad98-2c8cc8e0396f)
2018-06-27 10:31:16.195 +0200 DEBUG [3236:2416][source/iis/agent.c:1491] OpenAMHttpModule(): exit status: success (0), HTTP status: 404
2018-06-27 10:31:16.319 +0200 DEBUG [3236:2416][source/iis/agent.c:1732] OpenAMHttpModule(): request completed.
The problem here was manifold - IIS requires a relative path for a sub-request unlike apache (nginx and others work differently). Also taking advantage of newer technology. May be a docs implication (as HTTP_ shouldn't be needed)