How do I perform a SOAP login using pre-authentication and retrieve an auth token?

To perform a SOAP login with pre-authentication, send a POST request to `/service/soap` with a body containing the username and the preauth token (`<preauth>` element). The server responds with an `<authToken>` if successful. You can then reuse this token for subsequent SOAP operations like listing folders. Code examples for both the login request and folder retrieval are in the Zimbra SOAP API Development Guide 6 - Pre-authentication. For more SOAP basics, see the Zimbra SOAP API Development Guide.