ACK is not received Error.

[wzaatar]

Hello, everyone.

I currently have a 3CX setup involving a couple internal and external extensions and am experiencing the following issue, dunno if some of you ran into this:

When an internal extension calls an external extension, the call goes perfectly well.
When an external extension calls an internal extension, the calls goes perfectly well... For 30 seconds only when it breaks. I pulled out a trace from the log and you can notice a message after 30+ seconds as per the below at 22:52:32.568:

22:52:32.578 Call::Terminate [CM503008]: Call(27): Call is terminated 
22:52:32.578 Call::Terminate [CM503008]: Call(27): Call is terminated 
22:52:32.568 Call::Terminate [CM503008]: Call(27): Call is terminated 
22:52:32.568 InviteADS::onAckNotReceived [CM503019]: Call(27): ACK is not received
22:52:00.482 CallCtrl::onLegConnected [CM503007]: Call(27): Device joined: sip:[email protected]:5060 
22:52:00.482 CallCtrl::onLegConnected [CM503007]: Call(27): Device joined: sip:105@XXXXERASEDXXXX;transport=UDP 
22:51:53.372 CallCtrl::onSelectRouteReq [CM503004]: Call(27): Calling: RingAll100:101Ext.101102Ext.102103Ext.103104Ext.104@[Dev:sip:[email protected]:5060, Dev:sip:102@XXXXERASEDXXXX:5060;transport=UDP, Dev:sip:[email protected]:5060, Dev:sip:[email protected]:12338] 
22:51:53.362 CallCtrl::onIncomingCall [CM503001]: Call(27): Incoming call from Ext.105 to [sip:100@XXXXERASEDXXXX;user=phone]

A weird 'ACK is not received' message is appearing and the call is terminated. Any way to fix this?

Any help would be appreciated,

Thanks.

W.

 

[benrattigan]

Sorry this is the verbose log

16:11:14.343 [CM503008]: Call(11): Call is terminated
16:11:14.328 [CM503021]: Call(11): ACK is not received
16:11:03.437 Currently active calls - 1: [11]
16:10:42.296 [CM503007]: Call(11): Device joined: sip:[email protected]:40600;rinstance=78135f69701562d6
16:10:42.281 [CM503007]: Call(11): Device joined: sip:[email protected]:5060
16:10:42.265 [CM505001]: Ext.555: Device info: Device Identified: [Man: 3CX Ltd.;Mod: Voice Mail Menu;Rev: General] Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CX Voice Mail Menu] PBX contact: [sip:[email protected]:5060]
16:10:42.265 [CM503002]: Call(11): Alerting sip:[email protected]:40600;rinstance=78135f69701562d6
16:10:42.062 [CM503025]: Call(11): Calling Ext:Ext.555@[Dev:sip:[email protected]:40600;rinstance=78135f69701562d6]
16:10:42.046 [CM503004]: Call(11): Route 1: Ext:Ext.555@[Dev:sip:[email protected]:40600;rinstance=78135f69701562d6]
16:10:42.046 [CM503010]: Making route(s) to <sip:[email protected]:5060;user=vmail>
16:10:42.046 [CM505003]: Provider:[myphonenumber] Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [] PBX contact: [sip:myphonenumber@myexternalip:10661]
16:10:42.015 [CM503001]: Call(11): Incoming call from 01914157744@(Ln.10008@myphonenumber) to <sip:[email protected]:5060;user=vmail>
16:10:41.937 [CM503012]: Inbound office hours rule (unnamed) for 10008 forwards to VM:100
16:10:02.968 [CM503008]: Call(10): Call is terminated
16:10:02.953 [CM503021]: Call(10): ACK is not received
16:09:59.437 Currently active calls - 1: [10]
16:09:30.875 [CM503007]: Call(10): Device joined: sip:[email protected]:40600;rinstance=78135f69701562d6
16:09:30.859 [CM503007]: Call(10): Device joined: sip:[email protected]:5060
16:09:30.843 [CM505001]: Ext.555: Device info: Device Identified: [Man: 3CX Ltd.;Mod: Voice Mail Menu;Rev: General] Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CX Voice Mail Menu] PBX contact: [sip:[email protected]:5060]
16:09:30.843 [CM503002]: Call(10): Alerting sip:[email protected]:40600;rinstance=78135f69701562d6
16:09:30.640 [CM503025]: Call(10): Calling Ext:Ext.555@[Dev:sip:[email protected]:40600;rinstance=78135f69701562d6]
16:09:30.609 [CM503010]: Making route(s) to <sip:[email protected]:5060;user=vmail>
16:09:30.593 [CM505003]: Provider:[myphonenumber] Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [] PBX contact: [sip:myphonenumber@myexternalip:10661]

 

[RichardCrabb1]

The port forwarding is not correct. That's what needs to be sorted. Voip unlimited do not have an outbound proxy. They rely on correct mapping of ports.

 

[benrattigan]

Ext 555 is just voicemail as it was easy to test the timeout. How should the port forwarding be setup?

At the moment I have 5060 forwarded to the internal IP address of the server with 3CX on it. I have setup the firewall to allow 9000-9049 through but not forwarded to anything, should it be?

 

[nb]

Yes you need to forward all ports to 3CX int ip for some voip providers

5060 UDP (TCP if you need)
9000-9049 UDP
5090 BOTH (for tunnel)

Ack is not received is a popular symptom network problems, incorrect router configuration etc.

 

[RichardCrabb1]

Once having configured port forwarding, use the built in 3CX firewall test to prove that it is correct. Also, wherever possible use a static IP from your Internet provider.

Looking at your previous logs of the firwall test, port 5060 was being translated to 10482, so although configured it was actually translating the port number.

Kind regards
Richard Crabb

 

[dominicbatty]

I managed to get VOIP Unlimited working without using any inbound port forwarding and using NAT translation through my firewall with STUN. It actually fails the firewall check within 3CX but works perfectly and is extremely stable.

The downside to port translation that have found is that it requires you to turn off STUN hence specifying your external IP in the 3CX system, this is fine until your internet link fails over to a backup line and the external IP changes.

I've got a really good STUN tester, it would be interesting to know if you get the same results as me from it with VOIP Unlimited, drop me an email and I'll send it over.

Cheers, Dom.

 

[RichardCrabb1]

Hi Dominic,
I like to help people to establish the basic parameters first and then test under the most ideal solutions.

It is very interesting to hear that you have it working using STUN. I will drop you an email for that STUN tester.

Kind regards
Richard

 

[dominicbatty]

Richard, you are of course correct and my configuration is by no means "perfect". The port forward approach would be much more suited to my needs but my problem is that my external IP can change on occasion with link failover etc. What I actually want 3CX to do is use STUN purely to establish my external IP and nothing more so that it detects a WAN failover but with STUN it's all or nothing. I'll send you my STUN tester in the morning when I get into the office. Dom.

 

[benrattigan]

I have checked with our ISP who manage the firewall and they said 10482 was the source port.

Thanks
Ben

 

[RichardCrabb1]

Hello Ben,
I think that this is probably now on the wrong post but never mind. This problem really does look like an issue with NAT and port forwarding. That needs to be correct for it to work properly. Usually the source and destination port for SIP is 5060, so that might be incorrect.

Do the people who manage the firewall know what is needed to support port forwarding for the 3CX application?

Kind regards
Richard Crabb

 

[benrattigan]

These are the rules that have been setup in our firewall, 192.168.10.205 being the internal IP address of our 3CX server.

No Edit Enabled Rule Type Source Destination Options Log Description

1 Allow and Forward ANY This Gateway:9000 - 9015 (UDP) Forward To: 192.168.10.205

2 Allow and Forward ANY This Gateway:5060 - 5080 (TCP/UDP) Forward To: 192.168.10.205

3 Allow and Forward ANY This Gateway:5090 (TCP) Forward To: 192.168.10.205

4 Allow and Forward ANY This Gateway:3478 (TCP/UDP) Forward To: 192.168.10.205

5 Allow and Forward ANY This Gateway:5481 - 5483 (TCP/UDP) Forward To: 192.168.10.205
3cxconsole
6 Allow and Forward ANY This Gateway:10000 - 20000 (UDP) Forward To: 192.168.10.205
QoS Class: Urgent

7 Allow and Forward 91.151.2.130 This Gateway:Any Service Forward To: 192.168.10.205

8 Allow and Forward 91.151.2.133 This Gateway:Any Service Forward To: 192.168.10.205

9 Allow and Forward ANY This Gateway:9000 - 9049 (TCP/UDP) Forward To: 192.168.10.205


Thanks
Ben

 

[benrattigan]

Thanks for your help but discovered from ISP today that they cannot disable the port address translation on the Checkpoint firewall and so have suggested disabling STUN resolution in 3CX as we have a fixed public IP address. This has resolved the 30 second ACK not received issue but now we are getting one way audio only.

 

[jg-1]

We are getting the exact same problem with 3CX and checkpoint firewall - Either 30 second calls or one way audio. We got checkpoint to create voip domain but that made things even worse, with no calls being established at all.

Has anyone actually got checkpoint working with 3CX?

 

[smb1]

Out of interest, in the field Settings> STUN Server > Public IP to specify in Contact and SDP - do you have anything set. I know the field is greyed out if "Turn off STUN server" is not ticked but regardless of if it is greyed out or not is there anything set in there? Cheers, Dom.

PS. If so, what?

There was an old IP address greyed out on our 3CX box from a previous ISP. Ticked the box so this value could be deleted and then unticked, saved and restarted all services. Voila!

 

[Sarah Hastings]

That was some help at least for me worked to some en extent...thanks guys

 

[Grae]

I got this issue and have spend the day resolving it. The issue came from users on our WAN not the LAN.

Seems the 'Static Public IP' was interfering in our WAN users (who were connected to us but not through our internet connection), so under Settings > Network > STUN server I ticked "Turn off STUN Requests" and set the Static Public IP to the same as the NIC.

Completely solving the issue of calls hanging up after 30 seconds. I could have pointed them to the router that connects all the branches I guess, but I did just the same as the NIC and it worked and I don't wish to mess with it as it's working.