Interview Questions

Will IPSEC make firewalls obsolete?

Java Security,Windows code security, Windows Server 2003 Security,Internet Explorer 7 Security and Internet Firewalls questions and answers


(Continued from previous question...)

Will IPSEC make firewalls obsolete?

Some have argued that this is the case. Before pronouncing such a sweeping prediction, however, it's worthwhile to consider what IPSEC is and what it does. Once we know this, we can consider whether IPSEC will solve the problems that we're trying to solve with firewalls.

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'' [6]. 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).

Note that neither of these problems is what firewalls were created to solve. Although firewalls can help to mitigate some of the risks present on an Internet without authentication or encryption, there are really two classes of problems here: integrity and privacy of the information flowing between hosts and the limits placed on what kinds of connectivity is allowed between different networks. IPSEC addresses the former class and firewalls the latter.

What this means is that one will not eliminate the need for the other, but it does create some interesting possibilities when we look at combining firewalls with IPSEC-enabled hosts. Namely, such things as vendor-independent virtual private networks (VPNs), better packet filtering (by filtering on whether packets have the IPSEC authentication header), and application-layer firewalls will be able to have better means of host verification by actually using the IPSEC authentication header instead of ``just trusting'' the IP address presented.

(Continued on next question...)

Other Interview Questions