Understanding How NAT and Firewalls Affect UCaaS Services

NAT and your phone system

Network Address Translation (NAT) allows devices on your local network to share a public IP address. Briva Voice supports phones behind NAT using server-side traversal.

Common causes of calling problems

SIP ALG, SIP transformations, double NAT, and conflicting traversal settings can change call signaling and cause failed calls, dropped calls, or one-way audio. Have your network administrator review these settings with Briva Voice support.

Keep phones on networks that can route to each other correctly. If your modem and router both perform NAT, ask your administrator to review the network design.

Firewall configuration

Keep your firewall protections in place. Phones normally initiate outbound connections; avoid adding broad inbound port-forwarding or DMZ rules as a troubleshooting shortcut. Your administrator should confirm the required destinations and ports for your equipment with Briva Voice support.

Auto-provisioned devices receive their supported calling settings. For manually configured devices, ask support about SIP keep-alive and RTP proxy requirements. Devices with public IP addresses need a configuration review.

For help, contact support@brivavoice.com or call (469) 801-9561.