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Troubleshooting: Router / Firewall Configurations

Troubleshooting: Router / Firewall Configurations

Your Physical IP Devices and Softphone require certain configurations to be in place in order to ensure inbound calls can ring your device, outbound calls complete successfully, and no call quality issues are encountered. Each router handles their Firwall settings slightly differently but the information below will help steer you in the right direction.  As each router is different, we are unable to offer specific instructions how this is configured for your specific Router/Firewall. However, we can offer recommendations on best-practices that can be implemented by yourself or the person responsible for the installation and use of your Network and Internet Services. If after reviewing the information below you are still having trouble, contact our support team and we will do our best to help.

  1. SIP ALG – Make sure SIP ALG is disabled in your Router and Firwall as this will cause issues with call delivery and call quality.
  2. NAT – NAT issues can present themselves if you have multiple routers in your network setup. Check with your Network Admin to ensure you do not have a “double NAT” issues.
  3. Ports Used:  Referring to your Router/Firewall settings,  to ensure proper call delivery and quality, make sure that your Router or Firewall are configured to allow traffic on ports: UDP 5060-5065 and UDP 10000-20000
  4. QOS – QOS or Quality of Service is a setting available in most business-class routers and firewalls that helps to prioritize certain types of traffic over other types that are less sensitive to latency. For example, Voice over IP and Streaming require real-time communication or it will negatively affect your experience. Enabling QoS will help to ensure reliable Voice quality.
  5. For testing purposes, disable your routers Firewall and place teset calls. If the problem is no longer observed, Your Routers firewall is blocking the signal / connection.
  6. If you have followed the steps above but are still experiencing 1-way audio issues, contact your internet provider and ask if your Gateway/Router has SIP ALG enabled. Some Providers can only disable this setting on their end.
  7. Some ISP Providers do not allow customers to “disable” SIP ALG in their Gateway/Router. If after following the steps above, you continue to experience audio issues,
  8. In some cases, Internet Providers supply a Gateway/router where SIP ALG cannot be disabled. In these cases, they can typically provide an alternate model without this setting. Contact them to see what is available in your area. SIP ALG will break the connection between your device and our service and will need to be disabled for proper use with your UniTel Voice service, as with any Voice over IP Solution.


If you continue to experience trouble please contact our support team for further assistance.