SonicWall firewall VoIP configuration

SonicWall firewall VoIP configuration

The default firewall settings on SonicWall firewalls may cause issues with VentureTel VoIP traffic.  Some issues you may see are:
  1. Problems with phone registrations
  2. Dropped calls
  3. Phones not ringing
  4. One-way audio
The TZ400 is an exception to this requirement. For the TZ400 model, Consistent NAT should be enabled.

Disable Consistent NAT and SIP Transformations

  1. Go to VoIP > Settings.
  2. Uncheck the boxes next to Enable Consistent NAT and Enable SIP Transformations.

Disable Stealth Mode and RTSP

  1. Go to Firewall Settings > Advanced.
  2. Uncheck the boxes next to Enable Stealth Mode and Enable RTSP Transformations.

Additional Information

Known Issues

  • SonicWall TZ400/TZ500 requires Consistent NAT to be on. The exception to this would be if the TZ400 is on firmware version SonicOS Enhanced With this firmware version, disable Consistent NAT.
  • Firmware version 6.2.3.x causes Duplicate UDP ports regardless of NAT settings.
  • Firmware version 6.2.7 has DPI (deep packet inspection) under access groups on NSA series, which causes Call Quality issues despite rules added in.
  • Firmware version 6.2.7.x (and higher): 802.1p tagging breaks phone connectivity.
  • Additional testing has found that the "Consistent NAT" setting may need to be toggled depending on the firmware version in use. It may be necessary to toggle this setting on or off depending on the issues being experienced and then testing for stability. 
  • The following SonicWall models and firmware versions require Consistent NAT turned ON: SonicOS NSA 2600 Enhanced needs to be restarted in order for the setting to stick)
    • Related Articles

    • Configuring Fortigate Firewall for VentureTel service

      There are issues with the NAT configuration on Fortigate Firewalls, while the Firewall is supported, users with these devices will likely run into the following issues using a phone behind a Fortigate: Dropped calls One way or no way audio  Potential ...
    • Configure Cisco RV325 for VoIP

      The default firewall settings on Cisco routers have SIP ALG and SPI (Stateful Packet Inspection) enabled, which can cause issues with cloud based VoIP.  ​ Firewall Configuration Go to System Summary and ensure that the firmware is up to date ...
    • Adjusting Netgear Routers to Support VoIP

      Netgear ships their routers so that out of the box they rewrite SIP (VoIP) packets due to their stateful packet inspection (SPI) firewall & SIP ALG.  However, Netgerrs implementation of the SPI firewall and SIP ALG breaks the connection between VoIP ...
    • Configuring Dell Sonic Wall for VentureTel VoIP

      Step 1: Go to VoIP > Settings.  Step 2: Check Enable Consistent NAT, uncheck/disable everything else. Step 3: Click  Accept to save the settings.
    • VoIP Phone Troubleshooting - Start with a Reboot

      Problem Are you experiencing issues with your VoIP phone service? It might be something as simple as needing to reboot your phone. Solution Often, a quick reboot of your VoIP phone can resolve minor glitches that may be causing issues ...