Hi,
we have some Kamailios working as outboundproxy. So they get requests from internal systems and send them to different providers. From time to time, one provider returns a server as primary resource which is currently unavailable.
I guess if the internal systems connected directly to the target, they would remember the failed server and remember to always use the server with second priority at least until DNS refresh time. In our setup, since every request is "new" for Kamailio, it doesn't
remember, which host is reachable or not.
Example:
target: example.com
_sip._udp.example.com SRV resolves to:
10 192.0.2.42 5060
20 198.51.100.42 5060
30 203.0.113.42
5060
192.0.2.42
is unavailable. Still, Kamailio uses it for every new request and failover to 198.51.100.42 occurs only after timeouts hit.
Is
there a best practice for solving this? I have played around with the dst_blocklist settings, but that caused even more trouble because Kamailio started blocking requests to peers that have only one server in the record having a short hickup.
Thanks in advance for every input, as this is causing trouble every time we run into such a situation.