Methods and apparatus for implementing peer-to-peer relay. In one implementation, a method of detecting and recovering from violations in a peer-to-peer relay network includes: receiving a message at a peer system from a sending peer system connected to said peer system in a peer-to-peer relay network detecting a violation in said received message; and sending an alert message to each peer system connected to said peer system in said peer-to-peer relay network; wherein each peer system in said peer-to-peer relay network stores a connection limit defining a number of other peer systems up to which that peer system is permitted to connect, and each peer system stores a set of one or more relay rules for relaying data to other peer systems connected to that peer system.