Auto-discover optimal SIP connection settings by probing your endpoint with DNS resolution and SIP OPTIONS.
"udp", "tcp", or "tls". If omitted, both UDP and TCP are tested."running", "completed", or "failed"._sip._udp, _sip._tcp, _sips._tcp.port, transport, user_agent, detected_system (e.g., “Asterisk”, “FreeSWITCH”, “Kamailio”), codecs, and methods.