postfix TLS & ipv6 » Evaggelos Balaskas's logsseems that you need the below settings: #TLS smtp_tls_security_level = may smtpd_tls_ask_ccert = yes smtpd_tls_security_level = may smtpd_tls_loglevel = 1 #IPv6 smtp_address_preference = ipv6 so that postfix prefer ipv6 Vs ipv4 and use TLS if two mail servers support it ! # yum info postfix | egrep '^Version|^Release' Version : 2.10.2 Release : 2.rhel6 Tag(s): postfix, tls, ipv6
