Add basic fake NTLM server to test NTAuthentication round-trip scenarios

[filipnavara]

Add basic low-level NTLM exchange test. This is prerequisite for #29270, #62264 and test for the fixed scenario in #54101. It can also serve as basis for future tests for specific issues.

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Issue Details

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Ignore, just want to see CI results across all the system configurations.

Author:	filipnavara
Assignees:	-
Labels:	area-System.Net.Security, community-contribution
Milestone:	-

[wfurt]

I'm not sure if we really should go to the weeds of understanding NTLM internal in the tests.
I would much rather expand "echo server" e.g. corefx-net-http11.azurewebsites.net to provide reference NTLM server and run functional tests agains it.

cc: @rzikm @pavelsavara

[filipnavara]

I'm not sure if we really should go to the weeds of understanding NTLM internal in the tests.

I tried to avoid it for as long as I could but I snapped in the end. There were too many issues not covered by the tests and that could not even easily be covered by the tests.

I would much rather expand "echo server" e.g. corefx-net-http11.azurewebsites.net to provide reference NTLM server and run functional tests agains it.

If you are willing to host a test infrastructure I think that may provide a solid middle ground. However, the issue is not just HTTP. The SMTP GSSAPI authentication is currently broken on anything but Windows and there's no test coverage at all. NegotiateStream doesn't work on macOS and is not interoperable between systems (except maybe Linux and Windows if stars align, or if Kerberos is used).

We, at @emclient, have been hosting our own testing infrastructure for quite a while now and it's not easy. The Exchange servers bit rot constantly, the Windows Server 2019 machine on Azure needs to be restarted daily (seems to be a VM size issue and resource depletion).

I would be fine writing a simple echo SMTP server to cover the scenario above but I would need a commitment on hosting it and supporting it to be hammered by the .NET test infrastructure. Is that even something reasonable to ask?

[wfurt]

I would be fine writing a simple echo SMTP server to cover the scenario above but I would need a commitment on hosting it and supporting it to be hammered by the .NET test infrastructure. Is that even something reasonable to ask?

probably. It would finally close #19436 after 5+ years of waiting ;(
Perhaps off-line chat with me and @karelz would be beneficial.

[filipnavara]

Perhaps off-line chat with me and @karelz would be beneficial.

Definitely up for it. You know how to reach me.

[jstedfast]

Would love to know the conclusion of these discussions and whether MailKit would be able to take advantage of this.

[wfurt]

Sorry for the delay @filipnava. Is this something you still want to push forward? It seems like RC4 was part of #66879 so if we need it we should take it from there.
I think we can take it even if various OS bugs will make it fragile IMHO.

[filipnavara]

Is this something you still want to push forward?

Yes. I will rebase it and update the RC4 reference.

[filipnavara]

Yes. I will rebase it and update the RC4 reference.

Done. The remaining test failure is unrelated (#13757).

[wfurt]

LGTM.
Thanks @filipnavara