My client has aquired an zimbra solution for his email.

I wish to integrate zimbra with IronPort.

I modified the RAT and HAT table, also I modified the smtp routing to drop the messages to the MTA.

But what I wish and wonder if is it posible to authenticate and user in LDAP in order to stop spam and using my server as a reverse proxy smtp.

scenario.

user form outside the network sends aan email.

the IronPort reveceive the email and send this to the LDAP, if the user exsists in the LDAP then the email is sent to the MTA and all the rest of the story.

If the user doesnt exsists in the LDAP the email is droped by the IronPort as SPAM.

Why i want to do this, because right now if a chinese spammer sends and email using my domain it goes to the IronPort, this one sends it directly to the server and it flows normaly, it doesnt deny it.

sorry for my english and they way i explain. i am a noob explaining things