I have DNS SRV setup with 3 call servers for fail over purposes.
Zoiper is configured to register against my domain with a timeout of 60 seconds, so if the primary server goes down, it'll re-register against the backup server shortly after.
My issue is that Zoiper often decides to register against one of the backup servers instead of the primary server, despite the primary server being active and having other phones (hard and soft) registering fine. It looks like Zoiper does not respect the DNS SRV priorities and just picks one at random.
My DNS SRV records look like below (masked for obvious reasons):
_sip._udp.sub.domain.com has SRV record 10 10 5060 sub1.domain.com.
_sip._udp.sub.domain.com has SRV record 20 10 5060 sub2.domain.com.
_sip._udp.sub.domain.com has SRV record 30 10 5060 sub3.domain.com.
Above is just the UDP records, I have identical records for TCP (_sip._tcp) and TLS (_sip._tls).