Firewalls: an outdated defense

Firewalls emerged in the early 1990s as a countermeasure to the surge in malicious Internet activity. Initially they worked well, and they still afford some degree of protection. However, technological changes are quickly undermining the firewall, just as advances in warfare made the moat and drawbridge obsolete. The situation is dire enough that the security community must respond with a revolutionary new approach rather than settle for evolutionary improvements.