THIS IS AN AUTOMATED MESSAGE, DO NOT REPLY. A new Flyspray task has been opened. Details are below. User who did this - Iñaki Baz Castillo (ibc) Attached to Project - sip-router Summary - If no NAPTR then SRV must be queried for more than UDP Task Type - Bug Report Category - dns / dns cache Status - New Assigned To - Operating System - All Severity - Medium Priority - Normal Reported Version - Development Due in Version - Undecided Due Date - Undecided Details - As discussed in the maillist, Kamailio does the following lookups: 1. NAPTR cisco.com (no result) 2. SRV _sip._udp.cisco.com (NXDOMAIN) 3. A cisco.com -> Bingo -> use SIP over UDP to Cisco's web server :-( Step 2 is 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. More information can be found at the following URL: http://sip-router.org/tracker/index.php?do=details&task_id=253 You are receiving this message because you have requested it from the Flyspray bugtracking system. If you did not expect this message or don't want to receive mails in future, you can change your notification settings at the URL shown above.