NAT denial of service: An Analysis of translation table behavior on multiple platforms

Network Address Translation or NAT, is a technology that is used to translate internal addresses to globally routable addresses on the internet. It is used extensively in almost every network requiring global connectivity due to the current lack of IPv4 addresses. The primary mechanism used to facilitate the translation of internal addresses to external addresses and vice versa is the translation table. This study takes an in-depth look at how five different vendors: Cisco, Extreme, Linksys, VMWare, and Vyatta, implement the translation table during active NAT sessions. Additionally, this study analyzes the methodology required to fill a translation table and the Denial of Service that is a result of the attack. We consider the relative difficulty of accomplishing this task between the different platforms and protocols (TCP vs UDP vs ICMP). We conclude this study with steps that can be taken to prevent or mitigate the NAT DOS attack