Load balancer SIP Trunk

[paolobm]

Hi,

We are running 3CX the latest version on Debian and /etc/system/resolved.conf is set Cache=no.

When I ping the DNS the system is forced to resolve it, and balances it out to one IP or the other.

root@p02:~# ping sipconnect.xx
PING sipconnect.xx (40.69.xx.xx) 56(84) bytes of data.
^C
--- sipconnect.xx ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

root@p02:~# ping sipconnect.xx
PING sipconnect.xx (20.48.xx.xx) 56(84) bytes of data.
^C
--- sipconnect.xx ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

root@p02:~# ping sipconnect.xx
PING sipconnect.xx (40.69.xx.xx) 56(84) bytes of data.
^C
--- sipconnect.xx ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

root@p02:~# ping sipconnect.xx
PING sipconnect.xx (20.48.xx.xx) 56(84) bytes of data.
^C
--- sipconnect.xx ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

When I place outbound calls using 3CX PBX installed in the same machine mentioned above it only uses one IP instead of balancing it.

[ ] 8 INVITE [email protected] [email protected]:5060 9 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 9 INVITE [email protected] [email protected] 7 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 12 INVITE [email protected] [email protected]:5060 9 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 13 INVITE [email protected] [email protected] 7 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 16 INVITE [email protected] [email protected]:5060 8 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 17 INVITE [email protected] [email protected] 7 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 18 INVITE [email protected] [email protected]:5060 8 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 19 INVITE [email protected] [email protected] 7 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 21 INVITE [email protected] [email protected]:5060 9 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 22 INVITE [email protected] [email protected] 7 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 23 INVITE [email protected] [email protected]:5060 8 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 24 INVITE [email protected] [email protected] 7 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 25 INVITE [email protected] [email protected]:5060 8 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 27 INVITE [email protected] [email protected] 6 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 28 INVITE [email protected] [email protected]:5060 7 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 29 INVITE [email protected] [email protected] 6 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED
[ ] 31 INVITE [email protected] [email protected]:5060 7 127.0.0.1:5063 127.0.0.1:5060 BUSY
[ ] 32 INVITE [email protected] [email protected] 6 192.168.0.2:5060 40.69.xx.xx:5060 CANCELLED

Is there a DNS caching within the 3CX system, and how do I disable it or force it to be resolved every call?

I'm open to suggestions on how to fix this.

Thank you.

 

[YiannisH_3CX]

Hi @paolobm

You cannot disable the DNS caching of the 3CX system. The PBX will resolve the target initially as long as that target works it will keep sending requests to that target. In the event of failure the PBX will try the next target until all targets have been tried.