23 Feb
2023
23 Feb
'23
11:10 p.m.
On donderdag 23 februari 2023 12:09:53 CET Jon Bonilla (Manwe) wrote:
Again, fighting with MS Teams but this time it's a
kamailio question.
I have MSteams hosts in the dispatcher for OPTIONS and for
destination. Acording to MS you need to try sip.pstnhub.foo then
sip2.pstnhub.foo and sip3.pstnhub.foo
MS just assumes you don't know what DNS SRV is.
I was going to implement dispatcher failover as usual
ds_select_domain
(alg 8) with failure routes
Not needed.
but checking the SRV of the first domain
I see it already includes 4 hosts:
<snip>
Ironically, it's MS who doesn't understand DNS SRV, as all their SRV
records are invalid. The targets all point to aliases, which is
explicitly forbidden by RFC2782.
And in addition they use CNAME chains, which is bad practice.
Fortunately, as most "big" names in SIP don't understand DNS, Kamailio
has no problem with those mistakes.
So... If I have dns srv failover enabled in
kamailio... what would be
the point of the dispatcher failover?
None.
If DNS SRV is supported, just route to
sip:sip.pstnhub.microsoft.com;transport=tls
As you've seen, it resolves to the individual servers.
In case I only want failover in
case 408 or 5XX wouldn't the tm module do it for me?
It will.
--
Alex Hermann