![cannot connect to the zcs upstream server. cannot connect to the zcs upstream server.](http://1.bp.blogspot.com/-ybrgSLs8uEg/Va5Z-I9Vf5I/AAAAAAAADLo/WSqULantZus/s640/nimbus%2Bscreenshoot%2B-%2Bitlampung.com%2B.png)
Zmlocalconfig -e postfix_smtp_tls_security_level=may # if not already Zmlocalconfig postfix_smtp_tls_security_level Note that it is not usually possible to use "encrypt" here, as you cannot require remote MTAs to use encryption: Zmprov ms `zmhostname` zimbraMtaTlsAuthOnly TRUE # if not already SMTP zmprov gs `zmhostname` zimbraMtaTlsAuthOnly Zmprov gs `zmhostname` zimbraReverseProxyPop3StartTlsMode Zmprov ms `zmhostname` zimbraPop3CleartextLoginEnabled FALSE # if not already
![cannot connect to the zcs upstream server. cannot connect to the zcs upstream server.](https://linoxide.com/wp-content/uploads/2015/06/setup-zimbra-email-server-centos.png)
POP3 zmprov gs `zmhostname` zimbraPop3CleartextLoginEnabled Zmprov gs `zmhostname` zimbraReverseProxyImapStartTlsMode Zmprov ms `zmhostname` zimbraImapCleartextLoginEnabled FALSE # if not already IMAP4 zmprov gs `zmhostname` zimbraImapCleartextLoginEnabled Zmprov ms `zmhostname` zimbraMailClearTextPasswordEnabled FALSE # if not already HTTP zmprov gs `zmhostname` zimbraMailClearTextPasswordEnabled Restart services after making these changes. Zmprov ms `zmhostname` zimbraReverseProxySSLToUpstreamEnabled TRUEĪll authentication must be done over TLS/SSL. Zmprov gs `zmhostname` zimbraReverseProxySSLToUpstreamEnabled Require Proxy to connect to upstream via SSL Zmprov ms `zmhostname` zimbraMailMode httpsģ. Configure the mailstore to offer only encrypted HTTPS procotol: It is recommended to use only https here for highest security.Ģ. Please note, however, that some clients (such as ActiveSync devices) will not honor a 302 Redirect, and may try to pass unencrypted login information. Note: it is possible to use "redirect" here, which will redirect HTTP requests to HTTPS using a "302 Redirect" response code. Zmprov ms `zmhostname` zimbraReverseProxyMailMode https Zmprov gs `zmhostname` zimbraReverseProxyMailMode Configure the proxy to offer only encrypted HTTPS protocols (run this on every proxy): Most secure is to only allow secure methods of accessing the system however, be careful in making these changes, as all processes need to be configured to connect only to upstream encrypted listeners.ġ. References: TLS/STARTTLS_Localconfig_Values Services Zmlocalconfig -e ldap_starttls_required=true Require secure LDAP from mailboxd - should be set to "true": Zmlocalconfig -e zimbra_require_interprocess_security=1ģ. Zmlocalconfig zimbra_require_interprocess_security Require interprocess security - should be set to 1: Zmlocalconfig -e ldap_starttls_supported=1Ģ. Make sure LDAP is supporting STARTTLS - should be set to "1": If possible, use only Commercial CA-Signed Certsġ.
![cannot connect to the zcs upstream server. cannot connect to the zcs upstream server.](https://awanggadna.net/wp-content/uploads/2016/05/awangga-180x120.png)
This article is a Work in Progress, and may be unfinished or missing sections.