Sofia-SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification. It can be used as a building block for SIP client software for uses such as VoIP, IM, and many other real-time and person-to-person communication services. The primary target platform for Sofia-SIP is GNU/Linux. Sofia-SIP is based on a SIP stack developed at the Nokia Research Center.
New versions are currently being released on such a frequent basis that we can't keep this page updated. You will find all the information about changes, fixes, and latest releases at Sofia-SIP listing at SourceForge.
Sofia-SIP is licensed under the LGPL .