10 Configuring SBC for MS Teams

Businesses that want to optimize their investment in Office 365 and Microsoft Teams can utilize PortSIP's robust communications solution. PortSIP PBX for Microsoft Teams is a native Direct Routing integration that provides calling functionality and enables Teams users to get more done with an industry-leading cloud or on-premise PBX while keeping Teams at the center of the collaboration experience.

Features and Benefits

Enterprise-grade telephony for your Microsoft Teams users with a native user experience. Rich in PBX features:
  • Basic call controls
  • IVR and call handling
  • Automatic call recording
  • Call reports and analytics
  • Call queues
  • Full PSTN calls
  • Out-of-the-box native integrations to boost user productivity.
  • Provides enhanced PBX and telephony tools for your teams to deliver a true productivity boost for your projects.
  • Streamline the number of tools your users need to use, reducing cost, administration, and training.
  • Take advantage of the latest enhanced communications to save costs and increase the level of service your users enjoy.


  • Requires Microsoft TEAMS (Office 365) account with a domain in Office 365 with FQDN (fully qualified domain name) that you own.
  • Microsoft 365 E5 subscription plan or Microsoft Teams + Microsoft Phone System (add-on) for Teams users that wish to call or be called.
  • Make sure Prevent toll bypass and send calls through the PSTN setting in the calling policy of the user is set to Off. That will allow direct routing, especially if you are also using the MS phone system as well. It is found in the Microsoft Teams admin center under the left-side menu item Voice > Calling policies. Then choose the calling policy the user is using and make sure this setting is turned Off.
  • A trusted TLS/SSL certificate for your domain, for example, DigiCert, Thawte, Geotrust, Versign, a wildcard certificate is recommended.
  • The setup is a lot easier if the PBX runs on a public IP address. It is also possible to run the setup in a LAN with private IP, but this requires a proper setup of the firewall and additional steps on the PBX to make access from the Microsoft servers possible to the PBX.

Topology of the Interoperability Environment

In this guide, the interworking between SBC and Microsoft Teams with PortSIP PBX was done using the following topology setup:
  • Enterprise deployed with PortSIP PBX in its private network for enhanced communication within the Enterprise. The PBX has a static private IP address , no DMZ, and no public IP Address assigned.
  • Enterprise wishes to offer its employees enterprise-voice capabilities and to connect Microsoft Teams.
  • The SBC has a static private IP address which is deployed located at the edge of the enterprise network, DMZ is the static public IP address66.175.221.120.
  • The domain sbc.portsip.cc has resolved to the SBC static public IP
  • A trusted TLS certificate for the domain sbc.portsip.cc, or a wildcard TLS certificate for the domain portsip.cc .
  • The SIP domain is sip.portsip.cc for the tenant of PortSIP PBX.
  • The PBX user dials the Teams user phone number, the PBX route that calls to SBC, and the SBC route to Microsoft Teams.
  • When a Teams user dials the number, the call is routed to the SBC, then to the PBX, and finally to the extension as per the PBX inbound rule.