I'm trying to combat a spammer that seems to have the ability to send smap through my machine. I'd like to setup Zimbra so that the only emails it's allowed to send, are from our domain (domainx.org) instead of (domainy.com). I have authenication turned on, as well as TLS in the MTA settings for my domain.
I'm seeing a large increase in small emails going out, where their "From" emails are not from our domain. Is there a way to increase the amount of info being logged to show the username being provided to the SMTP server in zimbra.log?
Thank you for taking the time to read this, and thank you for any responses...