Need some clarification.
"with the IIS in Jetty" ?
What does this mean?
IIS is a separate product, a web server created by Microsoft.
Jetty is an open source Java web server.
Those would not be nested inside of each other in either way, and would not be aware of any specific data each other has (such as authn/authz details)
AJP is the old school Apache JServ Protocol.
Which is stuck at version 1.3 of the protocol since 2008.
It was a badly performing protocol when it was created, and now has a long list of bugs, quirks, and vulnerabilities present that have not been addressed in the past 14 years.
It's a dead protocol, we removed support for it when the AJP project group announced they were not going to update it any further. (During Jetty 7.x release, near the end of 2008)
The recommendations have been to migrate from AJP to up to date spec for HTTP/1.1 proxy behaviors (in Apache httpd terms, that's moving from `mod_ajp` to `mod_proxy`).
Jetty also supports JAAS, so you can choose any (third party) JAAS provider you want, even those that provide Microsoft specific features (like Windows authentication, Windows directory services, kerberos, etc).
So feel free to grab any JAAS implementation that fits your need and configure Jetty to use it.