DC++ is a free and open-source, peer-to-peer file-sharing client that can be used to connect to the Direct Connect network or to the ADC protocol. It is developed primarily by Jacek Sieka, nicknamed arnetheduck.As of 2008, DC++ had around 90% market share of the Direct Connect community.DC++ is a free and open-source alternative to the original client, NeoModus Direct Connect (NMDC); it connects to the same file-sharing network and supports the same file-sharing protocol.