Why is the custom X-Header I am adding to messages flowing through my Cisco Email Security Appliance (ESA) is not visible in my Exchange server?

Introduction

This document describes an issue when X-headers are missing / not visible on Microsoft Exchange server.

Background Information

We have recently had reports, from customers running Microsoft Exchange^™ of missing X-Headers. In environments where the Cisco Email Security Appliance (ESA) sends inbound email first to an Exchange 5.5 server, and the 5.5 server forwards the email to an Exchange 2003 server, there is an undocumented bug, in the Microsoft code, which strips and/or modfies the values of custom X-Headers. This bug persists even if both Exchange servers have the most current updates installed. Please follow the link below for information on resolving the issue.

$REFERENCES

• X-headers are assigned the same value instead of expected distinct values when you send an Internet e-mail message from an Exchange Server 5.5 computer