Firewalls are again becoming talk of the town. There are an enormous amount of opinions, including claims of a recent firewall revolution that have been proposed to completely change the firewall landscape. I will be the first to admit that the features and capabilities offered in today's firewall products are not the same as was offered in their original incarnation. But then again, traffic patterns and applications are not the same as they were when firewalls first hit the market.
If we look at the some of the original firewall products (bypassing the whole proxy versus stateful approaches), most products focused on a simple, yet powerful proposition – allow or deny specific protocols (applications) and most often the policy was to deny all, allow few exceptions. The general intent is to insert a barrier at the network border fending off unnecessary and potentially dangerous application traffic. These firewall policies were based on a common way to identify the application - the layer 4 protocol identifier.
Given this change in application delivery, it is natural for firewalls to evolve and address the new challenge of application security. Obviously the same principles exist as with the original firewall concept – allow / deny applications based on a corporate security policy. However, if every application uses a common web communication method such as HTTP - port 80, how would the traditional firewall implement appropriate controls? If port 80 is “allowed” through the firewall, it would open access to a plethora of applications, some of which could be contrary to the overall security policy.
This is where things get interesting regarding the so-called “firewall revolution” being claimed today, whereby applications are identified based on their content distinguishing, for example, between peer-to-peer (P2P) applications and hosted business applications. While this is a new way to identify applications, I don't agree it is a “revolution” because other security technologies have been doing this type of detection for quite a while, including intrusion prevention/detection systems (IPS/IDS). With IPS/IDS technologies, the ability to distinguish between multiple applications on a common protocol employs exactly the same principle as the proposed new firewall “revolution”. The new “revolution” isn't a revolution at all. It is nothing new, just a new way to use existing capabilities.
It seems disingenuous and just plain marketing hype to say that extending the application identification technology as part of a firewall policy is revolutionary. What is really happening is the evolution of the firewalls to meet the application evolution.
If there is anything revolutionary about firewalls today, it is the incorporation of content-based security technologies being integrated into the firewall, something that was previously thought to be impossible. The true revolution is in identifying threats within the application content, irrespective of the application, not just a new way to identify an application and allow or deny it.
A security solution that harnesses the power of application control and content-based security enforcement is the true state of firewall technology innovation – especially if you agree that firewalls should be deployed as defense mechanisms to eliminate threats versus an “allow-or-deny” paradigm for application access.