The invention provides an enforcement mechanism for limiting the propagation of content to a predefined proximity in a heterogeneous network. The protection mechanism determines the distance associated with wireless links of the heterogeneous networks and verifies that the distance is within the predefined proximity limits. The distance may be measured by evaluating the signal strength of received signals. The protection mechanism further uses round trip time determinations to enforce the proximity limits on wired or unknown segments of the heterogeneous network. Specifically, the round trip time associated with a wired or unknown segment may be determined using the round trip time associated with the wireless segments and the total round trip time of the network as a whole. The round trip time of the wired or unknown segment is then compared to a round trip time limit associated with the proximity requirement for distributing content.