The dns_ip6_lookup feature is disabled by default as of InterWorx Version 5.1.7. This means mail will not try to deliver via IPv6, unless manually configured. To enable sending over IPv6, first create a file called /var/qmail/control/dns_ip6_lookup with "1" as the contents:
echo 1 > /var/qmail/control/dns_ip6_lookup
[[email protected] home]# cat /var/qmail/control/dns_ip6_lookup 1 [[email protected] home]#Then, create a file called /var/qmail/control/senderip6, with contents following this format: domain: ip6 address. Example:
[[email protected] home]# cat /var/qmail/control/senderip6 iwtest.net:2001:db8:0:1:1:1:1:1 [[email protected] home]#