Adding the dimension of mobility to the engineering of complex software systems extends the scope of coordination. Since a mobile agent can roam a collection of different execution environments, physically distributed and possibly heterogeneous, interacting with both local resources and other mobile agents, both topology and security strictly relate to coordination. In this context, we propose an extension to the TuCSoN coordination model for Internet applications based on network-aware and mobile agents, which makes the coordination model coherently account for security and topology. TuCSoN defines a coordination space made up of a multiplicity of tuple centres, i.e., tuple spaces whose behaviour can be programmed to embed the laws of coordination, by means of specification tuples defining reactions to communication events.