nat_traversal doesn't handle IPv6 keepalives. It doesn't add [ and ] around IPv6 addresses and there's some bad parsing of SIP URI's in the code, assuming the first colon after "sip:" (not sips or tel) is a separator for port numbers. A better parser would be nice to use. --- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/362