understanding maillog postfix messages

[datadan]

I have been absolutely bombarded with these messages (125 in last 24 hours):

lost connection after HELO from unknown[68.116.205.54]

the IP changes from time to time ~20/30 different IPs that repeat.
I still am able to send/receive email.

Is this kiddie scripter sh*t or is it telling me I have a different problem?

 

[ericbrunson]

It's either spam drones or infected boxes probing for mail servers with known exploits. If you're up to date on your Postfix release you should have nothing to worry about.