open mail relay with ipv6??

[Mark Busby]

Is this an open relay using ipv6? If so how to block the ipv6 relay.
I thought after sendmail v8.9, all relay action was blocked by default.

maillog entry  
Nov 10 15:01:11 "hostname" sm-mta[8989]: mAAL021C008989: from=<jjack at panama-overseas.com>, size=4825, class=0, nrcpts=0, bodytype=7BIT, proto=ESMTP, daemon=IPv6, relay=localhost [IPv6:::1]
Nov 10 15:01:17 "hostname" sm-mta[8989]: mAAL021D008989: ruleset=check_mail, arg1=<security at bank0famerica.com>, relay=localhost [IPv6:::1], reject=451 4.1.8 Domain of sender address security at bank0famerica.com does not resolve
Nov 10 15:01:17 "hostname" sm-mta[8989]: mAAL021D008989: from=<security at bank0famerica.com>, size=3880, class=0, nrcpts=0, bodytype=7BIT, proto=ESMTP, daemon=IPv6, relay=localhost [IPv6:::1]

> sockstat -6
USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS
root     sendmail   8284  5  tcp6   *:25                  *:*
root     sshd       1520  3  tcp6   *:5960                *:*
root     ntpd       1010  5  udp6   *:123                 *:*
root     ntpd       1010  9  udp6   fe80:6::1:123         *:*
root     ntpd       1010  10 udp6   ::1:123               *:*
root     syslogd    927   6  udp6   *:514                 *:*