Why is a response to email showing as if the cc and reply to, were not me?

Question

From: [email protected]
Subject: Item Management - Stock-up Request: stocking 60 books instead of 2
Date: April 4, 2011 10:45:46 PM EDT
Cc: [email protected]
Reply-To: [email protected]
Funny ,but I copied from a received email, and what it shows cc and reply is NOT info@palotec but a different address that comes from my mail accounts?
anybody has any idea why?

Answer 1

Please clear some of the chaff from that description, and from the configuration.  I see no obvious relevance here with what you've discussed of your internal network, for instance, which makes me wonder why that information is included.  Not with an OS X Server box connected to a public static IP address, that is. 
What I read from the core of the description is a host box that's somehow changed its IP address.  You will need to figure out how (and why) that's happened.
Do you have network devices out in front of these hosts?   (Is there some other interconnection or other relevance of these other networks here?  Some networking device that might be present out in front of all these networks?) 
Are you operating on any dynamic IP addresses here?  (Or is DHCP involved here anywhere?)
If y'all want us to look at the external server configuration, please post your domain, and we'll have a look at that. (If you'd prefer not to post that, then please confirm that the forward and reverse DNS for your mail server and your MX record; ensure these all match.)
Clearing chaff is basic to debugging; you need to figure out what's involved and what's not involved (in the bug or the error or otherwise), and work your way through all that to the trigger and then the resolution.  Divide and conquer, or otherwise.