Calls dropping inbound and outbound

[infosec@primetrust]

Calls are dropping outbound after 15:30 consistently
Calls are dropping inbound after 00:30 consistently

I bought a ticket and support has been dragging their feet for 10 days now. send packet capture > try something support suggests > test and fail > send packet capture rinse and repeat every 24 hours ..... HELP

I have attached a packet capture both incoming and outgoing in both cases I am seeing a BYE message sent by the PBX to the SIP provider. I can assure you that the call was not ended by the VoIP phone.

I'm running a self-hosted Linux based 3CX PBX version 16.0.4.493 on Hyper-V

MAXCALLDURATION is 15800
SIP ALG is disabled

 

[Lugo Consulting]

Are you using a hostname for the SIP trunk? Also, did you whitelist the IPs from the SIP provider in the firewall of the PBX (in addition to your network firewall)? This was happening on our PBX and it was due to a Acknowledgement message was not received from the SIP provider due to the IPs not being whitelisted.

 

[infosec@primetrust]

Are you using a hostname for the SIP trunk? Also, did you whitelist the IPs from the SIP provider in the firewall of the PBX (in addition to your network firewall)? This was happening on our PBX and it was due to a Acknowledgement message was not received from the SIP provider due to the IPs not being whitelisted.

Yes hostname us-west-or.sip.flowroute.com is being used for SIP TRUNK
I have the ports specified by 3CX open to the PBX with no IP filtering. We are passing the Firewall check, all green.

 

[Lugo Consulting]

Turn your logging up to verbose in the management dashboard, restart your DB service, then generate the issue again. Once you do that, generate a support package and send it over to me so I can review the logs.

Also, can you do a packet capture from the firewall instead of the PBX, I want to see if there are packets being dropped at the firewall.

 

[infosec@primetrust]

I already have verbose support packages (a bunch of them) there is some sensitive information in there though, certs, etc. If you know what log specifically you are looking for ill attach it here.

 

[JohnS_3CX]

Hi @infosec@primetrust

In the capture you posted here (removed now for privacy reasons) we see that after the last 200 OK of the PBX, the provider does not respond with an ACK. Eventually the call is consistently dropped for this reason.

You need to ensure that your Flowroute trunk is created using our default template, because that is how we tested and validated it to work, and that's how it works successfully for other flowroute customers.

Let's see if the provider sends the ACK correctly when this default template is applied and the calls stop dropping. Specifically I would advise to pay attention to the value Select which IP to use in 'Contact' (SIP) and 'Connection'(SDP) fields and keep it default.