I just want to clarify the function of this new MTA server option, MTA Auth Host. According to your documentation, this option points to a zimbra store server so I guess your modified cyrus-sasl will SOAP that store server to authenticate SMTP user. Is it right? This option is introduced from the GA version, just curious how did cyrus-sasl do its job in the past? How could it know which store server to SOAP without the MTA Auth Host option?