Different ISP - issue with firewall

[Null]

Hello,
We are using 16.0 Update 8 (Build 9) on premise hosting. We have two connections ADSL and cable ISP provider. On both modems same local IP is assigned to 3cx instance and all ports are opened.

Issue is when we switch to cable ISP as we cant resolve connection to STUN servers, or for example license information. I managed to make calls without issue, but in some time android phone has not receiving push notifications with error

Failed to send FCM PUSH to device 8 Pro(Ext.100). Internal exception occured: Resource temporarily unavailable

Im quite sure im missing some IP/DNS settings? What should i check to resolve this issue for failback internet? Thank you for your time.

• 3CX Version, Professional Annual 16.09
• Server OS, Hyper-V with Debian 9
• Is the 3CX Server Hosted and where? At our location
• IP Phone Make/Model/Firmware -
• Provisioning Method: Local / VPN / STUN / SBC - Local SIP
• Trunk Provider or Gateway Make/Model - unsuported by 3cx
• Has the Firewall Checker passed: YES / NO - stuck on pining stun servers on cable net, all working on other connection. Ports are open on both connection, tested

 

[VasilisV_3CX]

Hi @Null,

The first major issue that sticks out is that the Firewall Checker isn't passing on the cable connection. Ensure that you've followed the guide on our Firewall Configurations. Ensure that SIP ALG has been deactivated, ensure port remapping is disabled as well. The following ports must all be forwarded, not just those checked by the Firewall Checker.

It is probably unrelated but ensure that you've also followed our guide on installing HyperV VMs.

 

[Null]

I will need to check my setup, but Im not sure where to look first.

When i switch to cable operator, from 3cx instance via shell im not able to ping google.com or any page. But for example, 3cx instance FQDN portal works without issue.

So, it seems that something is blocking some traffic, as "part of" internet works. Can anyone point me where to look? Firewall on router is not an issue, as i disabled it.