Question : How to restrict Helo command in Post from unknown IPs

We are running postfix as our SMTP. We want to restrict unknown SMTP connections on port 25 into our SMTP server.
We ideally want to restrict the helo  command to be initiated from any IP.
How can be this done ?

Answer : How to restrict Helo command in Post from unknown IPs

You can of course use all of these rejects :)