[asterisk-users] SRV DNS failover - dial to proxy list

[Matteo Piazza]

I'm looking for some documentationof the implementation of the SRV DNS 
on asterisk. I'm using asterisk 1.4.22.

1) From voip-info.org: "Currently, Asterisk only reads the first SRV 
entry without bothering with priorities and weights".
IS It still true? from my first tests I can see that asterisk is able to 
manage more than only the first SRV

2) I wanna configure the asterisk in this way: if the proxy with the 
highest priority is not reachable, IT tries to dial through the next 
proxy defined in the zone with a SRV record.


In my dialplan I have:
exten => _0461.,1,Dial(SIP/${EXTEN}@gorizia.tnet.it)

the asterisk recieve this answer at the DNS query
Domain Name System (response)
    [Request In: 1]
    [Time: 0.000352000 seconds]
    Transaction ID: 0x989a
    Flags: 0x8580 (Standard query response, No error)
    Questions: 1
    Answer RRs: 2
    Authority RRs: 1
    Additional RRs: 3
    Queries
        _sip._udp.gorizia.tnet.it: type SRV, class IN
            Name: _sip._udp.gorizia.tnet.it
            Type: SRV (Service location)
            Class: IN (0x0001)
    Answers
        _sip._udp.gorizia.tnet.it: type SRV, class IN, priority 0, 
weight 0, port 5060, target load.gorizia.tnet.it
        _sip._udp.gorizia.tnet.it: type SRV, class IN, priority 1, 
weight 0, port 5060, target failover.gorizia.tnet.it
    Authoritative nameservers
        gorizia.tnet.it: type NS, class IN, ns ns1.gorizia.tnet.it
    Additional records
        load.gorizia.tnet.it: type A, class IN, addr 172.25.18.68
        failover.gorizia.tnet.it: type A, class IN, addr 172.25.18.65
        ns1.gorizia.tnet.it: type A, class IN, addr 172.25.18.68

 From the asterisk console I have:
[2008-10-08 13:34:15]     -- Executing [060461829423 at users-distretto:2] 
Dial("SIP/tnn2678-08277a20", "SIP/0461829423 at gorizia.tnet.it") in new stack
[2008-10-08 13:34:15]     -- ast_get_srv: SRV lookup for 
'_sip._udp.gorizia.tnet.it' mapped to host load.gorizia.tnet.it, port 5060
[2008-10-08 13:34:15]     -- Called 0461829423 at gorizia.tnet.it

the load.gorizia.tnet.it is not reachable but asterisk is stuck here.

Any one have any clue?
Thanks for your time.
Matteo