[Users] t_relay does not follow RFC3263 "Locating SIP Servers"

Franz Edler franz.edler at ycn.com
Mon Sep 5 15:55:17 CEST 2005

Hi Bogdan,

> may you point the section from RFC 3263 which says that?
> the best I found is
>     "4.1 Selecting a Transport Protocol"

Yes exactly.

>    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.

Therefore the first thing should be to look for NAPTR records.
The next step (in case no NAPTR records are found) should be to look for SRV
records for transport protocols, which the client supports. In case of a TCP
enabled openser this should include _sip._tcp. Then the transport protocol
decision should take into consideration the priority values across all SRV
records, as you already mentioned.

This method enables comfortable control of transport protocols via DNS
records without manually selecting protocols in configuration files.

That would be fine.


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