Hi
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
2 | sip:sip.pstnhub.microsoft.com;transport=tls | 0 | 1 2 | sip:sip2.pstnhub.microsoft.com;transport=tls | 0 | 2 2 | sip:sip3.pstnhub.microsoft.com;transport=tls | 0 | 3
I was going to implement dispatcher failover as usual ds_select_domain (alg 8) with failure routes but checking the SRV of the first domain I see it already includes 4 hosts:
host -t srv _sips._tcp.sip.pstnhub.microsoft.com _sips._tcp.sip.pstnhub.microsoft.com has SRV record 10 0 5061 sip.pstnhub.microsoft.com.
_sips._tcp.sip.pstnhub.microsoft.com has SRV record 20 0 5061 sip2.pstnhub.microsoft.com.
_sips._tcp.sip.pstnhub.microsoft.com has SRV record 30 0 5061 sip3.pstnhub.microsoft.com.
_sips._tcp.sip.pstnhub.microsoft.com has SRV record 40 0 5061 sip4.pstnhub.microsoft.com.
So... If I have dns srv failover enabled in kamailio... what would be the point of the dispatcher failover? In case I only want failover in case 408 or 5XX wouldn't the tm module do it for me?
cheers,
Jon
Hello,
not answering your question, but I would stick to the three mentioned records and just do A-record lookup with dispatcher failover.
Cheers,
Henning
-----Original Message----- From: Jon Bonilla (Manwe) manwe@sipdoc.net Sent: Donnerstag, 23. Februar 2023 12:10 To: sr-users@lists.kamailio.org Subject: [SR-Users] Dispatcher failover when SRV failover is on?
Hi
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
2 | sip:sip.pstnhub.microsoft.com;transport=tls | 0 | 1 2 | sip:sip2.pstnhub.microsoft.com;transport=tls | 0 | 2 2 | sip:sip3.pstnhub.microsoft.com;transport=tls | 0 | 3
I was going to implement dispatcher failover as usual ds_select_domain (alg 8) with failure routes but checking the SRV of the first domain I see it already includes 4 hosts:
host -t srv _sips._tcp.sip.pstnhub.microsoft.com _sips._tcp.sip.pstnhub.microsoft.com has SRV record 10 0 5061 sip.pstnhub.microsoft.com.
_sips._tcp.sip.pstnhub.microsoft.com has SRV record 20 0 5061 sip2.pstnhub.microsoft.com.
_sips._tcp.sip.pstnhub.microsoft.com has SRV record 30 0 5061 sip3.pstnhub.microsoft.com.
_sips._tcp.sip.pstnhub.microsoft.com has SRV record 40 0 5061 sip4.pstnhub.microsoft.com.
So... If I have dns srv failover enabled in kamailio... what would be the point of the dispatcher failover? In case I only want failover in case 408 or 5XX wouldn't the tm module do it for me?
cheers,
Jon
-- PekePBX, the multitenant PBX solution https://pekepbx.com
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 -
Henning Westerholt -
Jon Bonilla (Manwe)