Router Info Sonicwall
We have a document on setting up a Sonicwall here:
We have seen that having IPS turned on with the check box for Prevent Low Priority Attacks checked can cause issues with some calls not going through. If you are having intermittent call failures disables this setting.
We have verified that enabling an inside--outside rule resolves the problems with dropped calls as it forces the Sonicwall to stick to port 5060. To configure this, create a NAT rule as follows:
Original Source: PBX Private IP
Translated Source: IP of the WAN interface (X1 IP for example)
Original Destination: Address Group for our SIP servers (22.214.171.124 or 126.96.36.199)
Translated Destination: Original
Original Service: Service Group including 5060 UDP and 10000-20000 UDP
Translated Service: Original
Inbound Interface: Any
Outbound Interface: WAN interface (X1 for example)
After that go to the Advanced tab and check the box for "Disable Source Port Remap" and click OK. The system will now talk to us from source port 5060.
VoIP phones behind a firewall running SonicOS 188.8.131.52 cannot make outbounds calls, although inbound calls and phone registration are working fine. Occurs when the internal SIP device uses a port that is different from the source port (the port associated with the Via or Contact fields), and when the remote device sends packets to this port, the firewall is not forwarding them to the internal device.