Support Forum
The Forums are a place to find answers on a range of Fortinet products from peers and product experts.
New Contributor

OS 7 Does no allow Internal (behind NAT) IP PBX to register to outside ISP service neither

Have en existing FGT30E that has been working ok. Internally I have an IP PBX that registers to the outside ISP. There are no SIP phones of any kind or colour. Simply an IP PBX, internally, and then I have a gateway to convert back to normal PST phones.

This set up with FGT30E has been working for 3 years. I also have an internal mail server with access to SMTP and WEB. All works.



As OS 7 came out purchased FGT40F and have latest OS 7.0.

In following what I think was the logic, I set it up with the corresponding virtual IP's as I did on FGT30E. Most of the settings are similar.

After putting the FGT40F in service, internet access works. email server works, web email works...............BUT, BUT............the IP PBX will not register to the outside neither can receive calls.

I am puzzled at to what could have changed in version 7 as the settings (virtual IP's and policies) are like in FGT30E.


Anyone would have a clue ?

Esteemed Contributor III



The diag debug flow would be my 1st start. And are you using SIP ? Do you happen to have sip-helper enable or ALG ?


I would read the following on this and what is the differences


Ken Felix






NO SIP, nothing to do with that. An IP PBX internal that does not register to the outside world, will not receive calls as is not registered, in the first brainier there.

The million dollar question was, why the rest would go out except the registration process ?????

Because then I realized that the bloody NUC had memory corruption and the IP PBX has crashed.............................

I got done myself.

But the NUC had been working for 3 years with the FGT30E, it collapsed just after I swapped that for the new F40F.

Coincidence ? No idea.

All is working now.

I failed to realized that there was no logic, no registration, I should have stopped there and then.


New Contributor

Problem fixed