In zimbra 5.18 Open Source version the header_checks are present in main.cf and also worked fine.
header_checks = pcre:/opt/zimbra/conf/postfix_header_checks
In Zimbra 6.01 Open Source version the header_checks is blank in main.cf. I have manually enter and save but when i restart postfix the header_check blank again.
Please kindly help me because Zimbra + MailScanner is not working due to this.