Postfix PCI Compliance in ZCS
|This article applies to the following ZCS versions.|
Reconfigure the Postfix SSL/TLS settings
1. Make a backup of /opt/zimbra/postfix/conf/main.cf in case you need to rollback or refer to after an upgrade.
2. Log in as root in the command line utility. Switch to the zimbra user account.
su - zimbra
3. Type the following commands:
postconf -e smtpd_tls_ciphers=medium postconf -e smtpd_tls_protocols=\!SSLv2 postconf -e smtpd_tls_mandatory_ciphers=high postconf -e smtpd_tls_exclude_ciphers="aNULL, MD5"
The SSL/TLS settings are now reconfigured. The changes will take effect immediately.
4. To ensure that your changes are not overwritten by a future Zimbra upgrade, you can set them in the local config.
zmlocalconfig -e smtpd_tls_ciphers=medium zmlocalconfig -e smtpd_tls_protocols=\!SSLv2 zmlocalconfig -e smtpd_tls_mandatory_ciphers=high zmlocalconfig -e smtpd_tls_exclude_ciphers="aNULL, MD5"
Reference - http://www.postfix.org/TLS_README.html
5. Use 'zmmtactl restart' to restart postfix.
This was originally written for ZCS 5.0.19, and has since been updated and tested in ZCS 6.0.4. Using the Qualys PCI scanning tool as the reference for passing the PCI network scan.