Hangup Problems with Inbound Calls

[Enoch]

Our Setup:
3CX Version: 12.5
Primary External Network: 65.xx.xxx.xx
Secondary External Network: 172.xxx.xx.xxx
IP Phones: Cisco IP Phone 7940

First of all, our 3CX has been in production for a while now. We have recently order new SIP trunking service along with an other external internet feed. The service pretty much worked off the bat. Both inbound and outbounds was able to make calls and received calls just fine.

Then I started to notice that the IP Phone was not hanging up after the call like it does with our other service. For example, when making an outbound call, the call would connect and when the recipient hangs up, the IP Phone continues to hold on to the call. Same with inbounds call; when the caller hangs up, the IP phone would continue to hold on to the call.

And through investigate with my SIP provider we found that the header information was going out with the wrong IP (65.xx.xxx.xx) instead of 172.xxx.xx.xxx.

So after a whole bunch of try and error, I'm now at this state:

Under the SIP Truck Settings:
- Advanced tab -> Registration Settings -> Which IP to use in 'Contact' and 'Connection' SIP fields -> using Use this IP Address: 172.xxx.xx.xxx
- Outbound Parameters -> Contact : Host Part -> Leave Default Value (default option: "ContactUri" usually, content of Contract field)

With the above settings, outbound calls are not hanging up correctly (whether it hangup is trigger by caller or recipient).

Now I am still having a problem with inbound calls. I have tried changing the options on Inbound Parameters:

- "ContactUri" usually, content of Contact -> Tried all options that have to do with "host"

Can anyone suggest the correct place to fix this problem?

 

[leejor]

We have recently order new SIP trunking service along with an other external internet feed.

It sounds as if there is some "confusion" caused by the introduction of a second public IP address. Is 3CX able to place, and receive calls on either one, or how is that managed?

 

[Enoch]

Technically the Primary IP is only used for Web Interface (management, reports, etc.). By design the new SIP Trunk should be using the Secondary for all inbound and outbound calls. We have a static route on the server which forces calls for this SIP trunk through the Secondary Network. And the SIP Trunk only communicates inbound through the Secondary Network.

 

[Enoch]

Anyone have any ideas which Inbound Parameters I should change to get this working?

 

[NickD_3CX]

No Inbound Parameters should need to be changed. All you should need to do is:
1) Remove the Default Gateway from NIC 2 172.xxx.xx.xxx
2) Add Windows static routes for all the IPs your Provider uses (don't forget their Media Servers as well).
3) In the Provider settings in the "Advanced" tab, set "Use this IP address" and enter the Public IP your second internet connections has (see below).

 

[Enoch]

@NickD_3CX I have already done that previously. That is how I got my outbound call hang ups to work properly. I'm still having problems with inbound call hang ups.

Are you sure there are no inbound parameters I can tweak?

 

[NickD_3CX]

I can't think of a reason why you would need to change the Inbound Parameters. If the calls are dropping after ~30 seconds, that probably means that the PBX is not receiving an 'ACK' message on the NIC it is expecting (NIC 2 in your case).

If this is the case, I would say the easiest way to see this is to run a capture on the Server on both Interfaces and see that there is an ACK message being received by the Phone System. If it does not, you should see it sending multiple '200 OK' messages.

Again, if this is happening, there was an issue in all versions prior to V12.5 where in the 200 OK message, the Phone System was sending the wrong IP address but that has been fixed in V14 (some other Providers just ignored it so not all where affected).

 

[Enoch]

OK... I guess we will do an upgrade to V14

 

[Enoch]

yup... V14 fixed the IP routing problem... now I have more problems to fix after the upgrade.