Many users (including myself) have had a problem involving resources on Outlook 2007 and Zimbra. See, for example, Resource accepts even when busy
Outlook 2007 appears to add two additional lines in the meeting invite that were not used in Outlook 2003. If you send an invite to a resource from Outlook 2007, you will see the following lines:
From Outlook 2003, only that middle line (X-MICROSOFT-CDO-IMPORTANCE:1) is sent. By comparison, the following is sent from the Zimbra web client (which does not overschedule resources):
Our workaround is to tell postfix to scan incoming messages for the problematic lines and to ignore (delete) them. This was tested on CentOS 5.1 x86_64, zcs-NETWORK-5.0.6_GA_2313.RHEL5_64.20080522105815. Here's how:
1) tell postfix to use body_checks
2) edit the body_checks file. We want to delete (postfix uses the IGNORE command to do this) lines that match the extra lines sent by Outlook 2007
[zimbra@mailhost ~]$ postconf -e body_checks=pcre:/opt/zimbra/conf/postfix_body_checks
3) Restart postfix
[zimbra@mailhost ~]$ cat /opt/zimbra/conf/postfix_body_checks
# REJECT For security reasons we reject attachments of this type
# REJECT Attachment type not allowed. File "$2" has the unacceptable extension "$3"
So far, we haven't found any other problems caused by this workaround. Give it a try and see if works for you.
[zimbra@mailhost ~]$ zmmtactl stop
[zimbra@mailhost ~]$ zmmtactl start