confirm delivery of email sent to SMTP server - set up ipv6 enabled MTA - used postfix, added
/etc/postfix/main.cf: # You must stop/start Postfix after changing this parameter. inet_protocols = ipv4 (DEFAULT: enable IPv4 only) inet_protocols = all (enable IPv4, and IPv6 if supported) inet_protocols = ipv4, ipv6 (enable both IPv4 and IPv6) inet_protocols = ipv6 (enable IPv6 only)
whew.