A network appliance controls access to network resources by identifying network paths passing through the network appliance to a protected network, drawings conclusions about the type of communications traveling along those paths, and then controlling, i.e. limiting, access to the protected network's resources for transmitting communications on a path-by-path basis. Recipient controlled mechanisms are used to control access to the recipient's network's resources, namely, restricting bandwidth, controlling allocation of SMTP or other connections, and packet level traffic shaping techniques including controlling of parameters of TCP and/or IP communications, such as TCP receive window size and Maximum Segment Size, or otherwise decreasing the amount of network traffic per unit of time passing through the network appliance. This limits the amount of network resources that may be used by incoming communications. Multiple network appliances may communicate with one another to operate in concert to protect a greater portion of network resources.