Problem connecting sip trunk gateway on v15

[Constantinos]

Hi to all
I have a problem with 3cx v15 on debian. My provider gave me a fritzbox to use as a gateway with 10 dlds. Gave me IP and all the info. At my system i have 2 Ethernet pci cards. 1 for internet and 1 to connect to fritzbox. i fix from terminal static IP for both pci cards. Now the problem is that when i assign static ip for the fritzbox the firewall checker cannot resolve stun and the system doesn't have internet on it. So my question is how to make 3cx to recognize which card is for internet and which is for gateway.
Thanks

 

[JasonNadeau]

I can't say for sure if it's the same in Linux, but if this was a windows server it would just be a matter of not putting in a gateway on one of the NICs.