Migration V7 => V11: Call drops after 32 secs with ACK not received

[stevi2312]

Hello,

I´m aware that I´m migrating from an ancient version to a very old version

On my Windows XP Pro machine with 3CX V7 everything works fine.
I did a backup, and imported it to a Windows 7 Pro machine with V11 installed.

Inbound works fine, but I have the famous "ACK not received" problem with outbound calls: Every call with one specific provider drops after 32 seconds. (Provider: keyyo, France)

With Sipgate and FreeVoIP I don´t have those problems, neither on V7 nor V11.

What I tried:
- Put 3CX server in DMZ
- Adapt W7 firewall with all 3CX and Keyyo recommended ports
- Disable W7 firewall

=> No impact at all.

If I have access to the system again, I´ll do a Wireshark scan, but maybe someone has already an idea what I could do ?

Thanks,
Chris

 

[lneblett]

This is generally an issue with a firewall on a router. Do a search for 32 seconds and you will see a number of post on the matter.

You should a) turn off any SIP ALG that may be in the router and, b) test the configuration using the firewall checker.

This is a start, what is the make/model of the router?

 

[stevi2312]

Thanks, I already read a lot about the ACK not received error.

The weird thing is, that with 3CX V7 on WinXP Pro it works flawless, with 3CX V11 on W7 Pro ("naked", firewall, defender, virus scanner deactivated) it drops the connection. I don´t know why the ACK passes on the old system, but not on the new one.

The router is from a french provider (bouygues, bbox) and has indeed 2 SIP-lines (only accessible via the box, no username/Password for those lines. But those lines didn´t seem to have an impact on the old system)

In my opinion there is either something wrong with my W7 installation, or the V11 handles calls to this specific provider in another way than V7.

 

[lneblett]

There are no time limits imposed by 3CX with regard to registrations of which I am aware (SIP timers). There are also no timers of which I am aware of with regard to Win firewall or most other 3rd party software firewalls.

This leads me back to the firewall in the router or possibly to the provider. You might also check the provider setting and validate the set-up. It could be a re-invite issue or similar.

Failing a wireshark capture on the WAN side, you may want to get with the provider to lend a hand in determining the issue.

 

[N_G]

This is 100% a firewall issue. Connection being dropped by the firewall.....

 

[swink]

Are your handsets on the same subnet as the phone system? I have seen this when they are not and stun is not config'd correctly on the handset.

 

[stevi2312]

Thanks for the replies.

Yes, the handsets are in the same subnet as the 3CX server.

I would also have thought that this is 100% a firewall issue, the things whichs strikes me is that with XP and V7 it works flawless. With Windows 7 (pro, firewall enabled with 3CX ports open or firewall even entirely disabled) and V11 (with backup from V7) => ack not received. (For the provider keyyo! sipgate or freevoipdeal are working)

I installed a 3CX v14 (no backup, manually configured) on W7 Pro (and even W10 Pro for testing purposes) => ack not received, call drops after 32 seconds (again, only Keyyo, other Providers are working)

Directly entering the keyyo SIP data into my CSIPSimple Android Client works also, call is not dropped (in the same network).

I´d like to buy the V14 upgrade, if I could get it to work.

 

[lneblett]

It is not a Windows firewall issue but with the router. What make/model?

 

[stevi2312]

It´s a proprietary router from my provider, Bouygues Telecom in France, in use now (like my 3CX Server) for several years.

https://www.bouyguestelecom.fr/offres-internet-bbox-pro
BBox Pro, internal SIP for 2 lines (coming in on VoIP, no SIP data provided, can only be used with the Box)
In internal rules of the box, port 5060 can not be forwarded, it´s reserved for the box´s sip accounts. Internal SIP can´t be turned off.

But even without forwarding of relevant UPD/TCP ports, it works fine with 3CX V7.

And even placing the 3CX in the DMZ (Windows 7/ 3CX V11 / provider keyyo) does not help.

 

[rsh]

Check your Nat settings (Open ports / firewall)
Also check STUN settings, mabye you entered a wrong custom WAN ipaddress?

 

[sergeyzh]

I have similar problem. I have a 3CX server behind the sonicwall NSA 4600. I have initially installed version 12 about a year ago, then upgraded to 12.5 without any issues (Windows Server 2012R2). I installed version 14 SP2 three days ago, and all my external extensions through 3CX tunnel (Port: 5090) have started dropping the calls after 32 seconds when extension calls out other extensions on the same network with server. I didn’t have similar problem with 12.5. It started after upgrade and issue just with 3CX tunnel.

 

[leejor]

I have similar problem.

Well...it's somewhat similar, but, it's a different router, different operating system, different port, and different 3CX version.

You may want to make use of Wireshark, on a PC connected using a hub (not a switch) between the modem and the 3CX router, to see if the correct incoming and outgoing SIP messages are actually there. You might spot an incorrect IP, or port that may point you in the right direction. Check the 3CX server log paying attention to the registration info.

 

[NickD_3CX]

The 3CX Phone System typically drops calls after precisely 32 seconds if in that time it hasn't received an ACK back.

As leejor suggested, if you run Wireshark you should see the 3CX Phone System sending out multiple messages and not getting an ACK as a response. If this is the case I would suggest focusing on 2 things:
1) In the messages the PBX is not getting an ACK for, check the 'Contact' SIP field to make sure it is requesting the ACK on the correct IP.
2) If the IP in #1 is correct, check that the Firewall is not blocking the incoming traffic for some reason on port 5060 (I would run the Firewall Checker as well if possible).

 

[satman1w]

This is 100% a firewall issue. Connection being dropped by the firewall.....

..Interesting thing is that it always drops the call after exactly 32 seconds, no matter what router is in question.
I myself have Mikrotik router which has no "hidden configs" or ALG-s (which are always the main suspect and culprit when e3CX fails). I have properly configured port forwarding, and a lot of "ACK is not received from sip:" (after exactly 32 seconds !!!!!) that started today...

I don't understand that there is no way to monitor all the SIP signalization and pinpoint the problem instead producing new versions of software carrying the same problems as previous...

Regards

 

[NickD_3CX]

I have never seen this being a software error, so it is not the software carrying a problem forward as versions progress, it is just some users repeating the same config mistake on all versions, or the are circumstances that happen on all versions that will cause this.

Anyhow, if it is always 32 seconds, this is ALWAYS caused by the 3CX Server not receiving the ACK. Possible reasons are:
- Firewall NAT Rules
- Contact field not containing the correct IP. This could be a result of: Public IP changing (static IP?), incorrect 3CX Settings during installation, etc...

As for monitoring the SIP signalling, there is a way, you can install Wireshark, capture a call that drops and examine the SIP information in it.

 

[satman1w]

I had the same problem and it was killing me....
I have excellent VoIP provider, ADSL connection with dynamic IP and Mikrotik router. I've tried with 3CX V12.5, V12, V14, V8..... and the problem remains the same. Sometimes it works for 3,4,5 days and then .... every incoming call drops after 30-32 seconds with "ACK not received" !
So, I checked all the 3CX and Mikrotik parameters including the legendary "disable the SIP helper" which (on Mikrotik) does not make any change !!
Even found an article by Mr Nick Galea in which he claims that the problem definetely lies on the router, more precisely - in the firewall.

The fact is that I solved the problem by scheduling 3cx services restart once a day (after the router receives a new IP) !!
So the problem is definetely "WITHIN THE SOFTWARE" !!!

 

[dmayer]

I had the same problem and it was killing me....
I have excellent VoIP provider, ADSL connection with dynamic IP and Mikrotik router. I've tried with 3CX V12.5, V12, V14, V8..... and the problem remains the same. Sometimes it works for 3,4,5 days and then .... every incoming call drops after 30-32 seconds with "ACK not received" !
So, I checked all the 3CX and Mikrotik parameters including the legendary "disable the SIP helper" which (on Mikrotik) does not make any change !!
Even found an article by Mr Nick Galea in which he claims that the problem definetely lies on the router, more precisely - in the firewall.

The fact is that I solved the problem by scheduling 3cx services restart once a day (after the router receives a new IP) !!
So the problem is definetely "WITHIN THE SOFTWARE" !!!

No, it is in your configuration. You have a dynamic IP that changes everyday? You do realize that 3CX will send out data packets using the IP address specified in the management console, right? If the destination replies based upon an old IP address that would cause a bit of a problem, hence 3CX not receiving the ACK from where it sent the data to. Dynamic IP isn't a supported configuration using SIP, if you had a PSTN gateway and did not talk out to the internet, you would be fine.

http://www.3cx.com/blog/docs/configure- ... r-testing/

See Nick's post here about it as well:
viewtopic.php/a-couple-of-questions-about-internal-and-external-fqdn-43393.html?forum_uri=a-couple-of-questions-about-internal-and-external-fqdn&start=&t=43393#p177684

We use Mikrotik routers here with 0 issues, but all of our customers that talk to SIP or the Internet have static IP's, VoIP is a service that does not run well over dynamic IP's.

If you contacted your VoIP provider about this issue and mentioned dynamic IP, they should have honestly pointed out that being the issue.