Techniques and systems for media stream dissemination using a peer-to-peer network are described. A described technique includes joining a peer-to-peer network as a peer; determining whether to be a first source node in the peer-to-peer network; retrieving a media stream from a server based on being the first source node; dividing the media stream into separate portions in a manner consistent with division performed by one or more second source nodes in the peer-to-peer network; generating messages that include the portions, respectively, for dissemination on the peer-to-peer network; and posting the messages to the peer-to-peer network, where the messages are generated such that peers in the peer-to-peer network are able to identify duplicative messages that are posted by the one or more second source nodes, the duplicative messages being based on the media stream.