[Kamailio-Users] Question regarding TM module DNS failover with SRV records

[Nathan Angelacos]

According to the 1.5.x TM module documentation,
DNS failover is triggered by a 503 reply or a timeout.

When using SRV records, it appears a 503 triggers the failure_route instead.

Given:

host -t srv _sip._udp.voip.example.net
  _sip._udp.voip.example.net has SRV record 1 0 5060 
fast-server.example.net.
  _sip._udp.voip.example.net has SRV record 2 0 5060 
slow-server.example.net.

On an invite to voip.example.net, if fast-server does not respond within 
"fr_timer" seconds, t_relay fires off a serial branch (t_on_branch is 
triggered) and the invite goes to slow-server.

If fast-server responds with a 503, the t_on_failure route is triggered 
instead, and the invite is not sent on to slow-server.

If its not a bug in the module, does anyone have  clues of how to coax 
the next DNS SRV record out of the t_on_failure route?  Or what can be 
done to get t_relay to consume the 503?

Thanks!