VoIP SIP trunk - incoming packet dropped "connection to be closed"

janjezek

Hello everyone,

we have outgoing calls via SIP trunk working but incoming calls are dropped. In the packet monitor, the reason is "Packet dropped - connection to be closed". I run into this error on yet another location, another firewall, another provider, so I am curious what that could be. In the knowledgebase I haven't found neither helpful explanation of this error, nor troubleshooting steps.

SonicOS 6.5.4.8/6.5.4.9, NAT consistency Off, SIP transformations Off

Any advisory/idea would be highly appreciated.

Cheers,

Jan

Nevyaditha

Hi @janjezek ,

Can you please confirm the NAT Policies are set up appropriately on the firewall for the inbound call flow?

https://www.sonicwall.com/support/knowledge-base/how-to-configure-voip-to-use-any-voip-phone-system-best-practices/210615132522720/

https://www.sonicwall.com/support/knowledge-base/common-mistakes-with-port-forwarding/200530122019613/