@miconda i tested with master branch.its working fine.it will be good if you can commit all changes related to ipv6 to all stable releases specially to 5.x.x branches.reference to following pull request: https://github.com/kamailio/kamailio/pull/1319 https://github.com/kamailio/kamailio/pull/1315 https://github.com/kamailio/kamailio/pull/1291