Will IPSEC make firewalls obsolete?

IPSEC (IP Security) refers to a set of standards developed by the Internet Engineering Task Force (IETF). There are many documents that collectively define what is known as ``IPSEC'' [4]. IPSEC solves two problems which have plagued the IP protocol suite for years: host-to-host authentication (which will let hosts know that they're talking to the hosts they think they are) and encryption (which will prevent attackers from being able to watch the traffic going between machines).