In order to set IPv6 under MTA(VOIP) you need to set your DUT as below:
CM IPv4 and IPV6 policy set under option: [17] (dhcp6-cablelabs-config) set as below
v6 ONLY:
(enterprise-id 4491((tftp-servers 32 2001:0:130::50)(config-file-name 33 xxxcfg)(syslog-servers 34 2001:0:130::50)(rfc868-servers 37 2001:0:130::50)(time-offset 38 8h)(ip-pref 39 2)(cablelabs-client-configuration 2170 (primary-dhcp-server 1 192.168.1.50))(cablelabs-client-configuration-v6 2171 (primary-dhcpv6-server-selector-id 1 20:01:00:00:01:30))))
dual ONLY:
(enterprise-id 4491((tftp-servers 32 2001:0:130::50)(config-file-name 33 xxxcfg)(syslog-servers 34 2001:0:130::50)(rfc868-servers 37 2001:0:130::50)(time-offset 38 8h)(ip-pref 39 5)(cablelabs-client-configuration 2170 (primary-dhcp-server 1 192.168.1.50))(cablelabs-client-configuration-v6 2171 (primary-dhcpv6-server-selector-id 1 20:01:00:00:01:30))))
MTA IPv4 and IPV6 policy set as below
(enterprise-id 4491((tftp-servers 32 2001:0:130::50)(config-file-name 33 xxx.bin)(syslog-servers 34 2001:0:130::50)(rfc868-servers 37 2001:0:130::50)(time-offset 38 8h)(cablelabs-client-configuration 2170 (primary-dhcp-server 1 192.168.1.50))(cablelabs-client-configuration-v6 2171 (primary-dhcpv6-server-selector-id 1 01:02:03:04:05:06:07:08:09)(provisioning-server 3 (flag 0; provisioning-server prov.ht.com.))(kerberos-realm 6 BASIC.1.))))
