The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks. It provides for transmitting blocks from sources to destinations which are identified by fixed length addresses. The protocol is specifically limited in scope to provide the functions necessary to deliver a datagram from source to destination, and there are no mechanisms for other services commonly found in host-to-host protocols.

In recent years the Internet has experienced dramatic growth rate. Large organizations, small companies, and private people alike are joining in every day. This has brought forth two critical issues concerning the current implementation of the Internet Protocol - the IPv4 - security and availability of addresses.

IPv4 relies on 32bit addressing scheme which was sufficient when IPv4 was deployed. Recent growth however, has put a strain on the address space, and a new addressing scheme is needed. As this is not an immediate concern, and short-term solutions to prolong the availability of addresses have been deployed while waiting for transition to a new version of the protocol which will allow 128bit addressing (IPv6).

A more urgent problem, however, is data security, or actually the lack of it. In its growth, the Internet started attracting not only academic circles and research labs, but also banking, commerce, and business. It is a growing market area which is yet to be exploited to its full potential. The lack of security is a rather crippling factor. IPv4 does not provide measures which would assure that the data being received by the end station has not been altered during the transmission, or that it actually came from the claimed source. Bank transactions can be altered, credit card numbers can be stolen, false data can be fed to companies, and so on. The most often found current practice is the use of application layer security. This however, does not protect from all forms of attack, and does not encourage standardization.

In order to enforce security in the existing systems, many companies hid themselves behind firewalls. These are systems which stand between a LAN (which is considered to be a trusted network), and the cruel world outside. Firewalls attempt to analyze the incoming packets of information and determine if they contain valid information. This might seem good, but it restricts access to the outside from within the LAN.

Because of the need for an upgrade anyway, it was logical that the new version of the Internet Protocol - IPv6 - should contain a native security system which would allow the users to communicate securely. At the same time, it must be realized that because the Internet is a vast and complex network, the transition to the new version of the protocol will not be immediate, and hence the security implementation should be such that it would be compatible, and adaptable to IPv4.

Internet Engineer Task Force (IETF) has agreed on a set of rules which would define security measures in IPv6, and has gathered them under the name IP Security (IPSEC).