Brief one sided audio, New firewall

[Ianing]

I replaced my firewall this past week which was unpleasant. I've worked out all but one of my issues.
If I call in from outside I miss the first few seconds of the IVR.
If I call my cell phone from a deskset, cell phone picks up fine. But receives nothing for about the first 6 seconds, can transmit. Timing can vary. The deskset can receive fine for at least 4 seconds. Then there is no audio on either side for a second. Then they work fine.
Was fine before new firewall

So in summary it appears to me the initial connection is limited for a few seconds. Then after a brief loss of audio everything works.
Can someone give me some tips on where to resolve this?

• The new firewall is a sonicwall nsa2700, v7 UI. One WAN currently. VLAN for all VoIP. Firewall check passed!
• On prem Hosted debian 9 3CX server, Pro 16.0.8.9
• Flowroute sip, Yealink T23g phone.

Really appreciate any time you offer me. I've spent more hours then I wanted to trying to transfer my configuration from the old UI to the new UI. Then I had to search out the changes that were hindering my 3CX server. Thanks!

 

[JohnS_3CX]

Hi,

Have you by any chance read this yet?
https://www.3cx.com/docs/sonicwall-firewall-configuration/

 

[Ianing]

Hi,

Have you by any chance read this yet?
https://www.3cx.com/docs/sonicwall-firewall-configuration/

Yes I've referenced that extensively with my initial deployment, and now with replacing the firewall with a newer model Sonicwall.

Unfortunately this document is a bit outdated now with the v. 7 UI.

 

[JohnS_3CX]

Ok I won't be able to assist you with it but perhaps other members with experience with that model can.

Sounds like you opened the ports fine, but the unit is dropping some of the traffic. Ensure you do not have any of the following active

- SIP Transformations
- SIP Helper
- SIP ALG
- Anything similar that manages SIP on the firewall level

 

[jcostlow]

I have a TZ 570 running v7. Have you gone to network, voip and disabled SIP transformations and enabled consistent NAT?


Sometime the App Control will cause issues but that would typically show on the log.

 

[Ianing]

Thanks Jcostlow. I had left Consistent NAT off because I hadn't noticed a difference But I'll re-evaluate that.

Yeah I expected App Control would cause a problem. But the biggest issue I had was that DPI was disabled on the zone, but I didn't realize it was also controlled in the access rules.

I have a TZ 570 running v7. Have you gone to network, voip and disabled SIP transformations and enabled consistent NAT?
View attachment 21503

Sometime the App Control will cause issues but that would typically show on the log.