Testing External Authentication

Hello;

I am trying to configure external authentication.

authentication.chain=external1:external,alfrescoNtlm1:alfrescoNtlm
 
external.authentication.proxyUserName=secretAccount
external.authentication.enabled=true
external.authentication.defaultAdministratorUserNames=admin
external.authentication.proxyHeader=X-Alfresco-Remote-User

Then I used a simple rest client to make a few calls to

/alfresco/service/api/login?u={1}&pw={2}

First I made a call as a user to get a ticket. This resulted in 123

Then I made a call with the secret account to get their ticket. 321

Then I made a call with the secret account and with the header set to the original user's username. I still got 321.

This tells me the external authentication is not working; or my test is flawed.

Can someone help me diagnose this?