Modern networks deploy middleboxes to support numerous advanced processing capabilities such as firewalling, traffic compression, and caching. Despite the widespread deployment of these features, they are nevertheless invisible to the end hosts using the network. We designed ‘network calls’ (netcalls) to allow end hosts to make function calls to the network processing their traffic, allowing the end hosts to invoke and configure the numerous advanced features provided by the networks their traffic traverses. For example, we built a web server that, upon detecting it is under attack using application-layer knowledge, adds additional filters to the firewalls in its network. A key challenge to netcalls is that we want to allow advanced configuration to end hosts not only in their local network, but in any network their traffic traverses. Thus, the netcalls architecture lies primarily in two components: an intra-domain protocol for end hosts to invoke function calls with their network provider, and an inter-domain protocol, by which providers invoke features in each others networks on behalf of their clients. Source code forthcoming.