The GNU Gatekeeper (GnuGk) is a full featured H.323 gatekeeper, available freely under GPL license. It forms the basis for a free IP telephony system (VOIP).
It is being used commercially by many organizations to provide VOIP services.
- Executables for Linux, Windows, MacOS X, Solaris, FreeBSD, OpenBSD and NetBSD
- can be run as a Windows service
- accounting and call authorization via SQL database, Radius, file or external application
- database drivers for ODBC, MySQL, Postresql, SQLite and Firebird
- flexible call routing
- number rewriting (calling and called)
- support for NAT traversal
- full H.323 proxy
- TCP interface to applications
- CTI functions (eg. VOIP call-center, call transfers)
- gatekeeper clustering support (neighbors, parent/child, alternates)
- H.235 security
- graphical user interface
- it’s free, including source code