Traditionally, cyber initiatives have focused on the upper levels of the OSI stack, with particular emphasis on non-technology defenses to human-targeted weaknesses. While exploitation of the user is the simplest and most prevalent type of attack, defenses against a sophisticated enemy require protection of the entire network. This paper focuses on an often-overlooked portion of the network, the transport layer. The threat envelope is described, along with a suggested set of response actions, mitigations, and counter-measures to keep the network safe. In addition, this paper explores the possibility of active defense mechanisms for preventative/predictive manipulation of the transport layer.