Ventrilo is proprietary VoIP software that includes text chat. The Ventrilo client and server are both available as freeware for use with up to 8 people on the same server. Rented servers can maintain up to 400 people. The Ventrilo server is available under a limited license for Microsoft Windows and Mac OS X and is accessible on FreeBSD Kopi, Solaris and NetBSD. The client is available for Windows and Mac OS X. However, the Mac OS X client is still unable to properly use most servers because of a lack of support for the sparsely used GSM codec. Flagship Industries does not offer a Linux Ventrilo client. Ventrilo supports GSM Full Rate and Speex codecs.