TCP/IP Illustrated, Volume 1: The Protocols, 2nd Edition

7. Firewalls and Network Address Translation (NAT)

7.1. Introduction

During the early years of the Internet and its protocols, most network designers and developers were from universities or other entities engaged in research. These researchers were generally friendly and cooperative, and the Internet system was not especially resilient to attack, but not many people were interested in attacking it, either. By the late 1980s and especially the early to mid-1990s the Internet had gained the interest of the mass population and ultimately people interested in compromising its security. Successful attacks became commonplace, and many problems were caused by bugs or unplanned protocol operations in the software implementations of Internet hosts. Because ...