GNU SIP Witch
GNU SIP Witch is free SIP server software with peer-to-peer capabilities from the GNU Project. It is the GNU implementation of the Session Initiation Protocol, which is used for the routing of calls.
Availability
SIP Witch is released as free software under the terms of version 3 or later of the GNU General Public License. It is designed for Linux, macOS, BSD and Windows.Technology
SIP Witch is written in the programming language C++ and uses the uCommon, eXosip and GNU oSIP libraries.Features
The software enables Voice over IP as part of a self-organising Peer-to-peer telephone network.It supports features like call forwarding, call distribution, call hold, presence information and messages, supports encrypted calls and also enables NAT traversal to establish the peer-to-peer connections.