GNU Gatekeeper
GNU Gatekeeper (abbreviated as GnuGk) is a free software project that implements an H.323 Gatekeeper based on the OpenH323 or H323Plus stack. A gatekeeper provides address translation, admissions control, call routing, authorization and accounting services to an H.323 system defined on the H.323 standard by ITU-T. == Features == GnuGk's set of features include: Created for Linux, Windows, macOS, Solaris, FreeBSD, OpenBSD and NetBSD A policy-based flexible routing mechanism Calling and called numbers rewriting, including CLI rewriting Full H.323 proxy, including Real-time Transport Protocol (RTP) and RTP Control Protocol (RTCP) media channels, and T.120 data channels NAT traversal using a number of protocols, including H.460.17, H.460.18 and H.460.19 IPv6 support (incl.