Flexisip SIP proxy server released

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The free linphone.org SIP service is running since 2011, allowing Linphone users to create their SIP addresses in order to communicate together. The SIP server software powering this service, whose name is "Flexisip", is now released with an open-source license.

Flexisip is a SIP proxy server implementation compliant to RFC3261, written in C++11.

The server has the following key features:

  • Transports: SIP/UDP, SIP/TCP and SIP/TLS
  • NAT aware with built-in media relay module and stun server
  • digest authentication based on external SQL password database or static password file
  • Registrar
  • Routing based on registrar database or static route file, with forking
  • Push notifications systems for reliably notifying mobile apps of incoming calls or messages
  • High level event logging for activity monitoring
  • High availability and cluster mode operation for large deployments 

Thanks to its modular architecture and its limited number of required dependencies, Flexisip can also perfectly run on small hardwares (embedded systems).

More information on the pages dedicated to the project on this site: