2012/11/6 Klaus Darilion klaus.mailinglists@pernau.at:
Kamailio does the following lookups:
- NAPTR cisco.com (no result)
- SRV _sip._udp.cisco.com (NXDOMAIN)
- A cisco.com -> Bingo -> use SIP over UDP to Cisco's web server :-(
Then really wrong...
After NAPTR query (with no result) it should look for SRV records for TLS, TCP and then UDP (maybe also SCTP) in an order configured by local policy (Kamailio DNS settings).
This is really clear in RFC 3263 section 4.1:
If no NAPTR records are found, the client constructs SRV queries for those transport protocols it supports, and does a query for each. Queries are done using the service identifier "_sip" for SIP URIs and "_sips" for SIPS URIs. A particular transport is supported if the query is successful. The client MAY use any transport protocol it desires which is supported by the server.
If no SRV records are found, the client SHOULD use TCP for a SIPS URI, and UDP for a SIP URI. However, another transport protocol, such as TCP, MAY be used if the guidelines of SIP mandate it for this particular request.
Why is this not implemented?
Issue open at http://sip-router.org/tracker/index.php?do=details&task_id=253
-- Iñaki Baz Castillo ibc@aliax.net