Firewalls in the Data Center…security or bottleneck?

In response to a recent post questioning why someone would want to run a firewall-less network, Lori MacVittie tweeted that performance might be one reason with a link back to a a recent article she wrote:

The Firewall in Front of the Data Center

In her article, MacVittie is not advocating doing away with firewalls, but she is questioning the dogma of a firewall in the data center, specifically firewalls protecting Web Services.  The basic premise is that firewalls can be a bottleneck, or worse a point of failure, due to performance issues or denial of service attacks.  I completely agree that this design should be questioned in this case.  That may seem odd coming from a firewall management vendor like FireMon, but firewalls are not the end-all of security and we don’t advocate ineffective use of the technology.

Public facing services, which are most susceptible to denial of service attacks, have a unique access requirement of allowing everyone.  When you have a service that is needed by everyone, access control is not really controlling much and does raise the question of why implement a firewall at all. However, this does not mean there is not a role for the firewall in this architecture.  In fact, it is now critical to ensure access is

The Firewall Inside the Data Center

controlled from this public system to any other system on the network.  In the traditional sense of a DMZ, no access should be allowed from this public system to any other protected system to protect the network in the event of a breach.  Addressing this access control requirement results in implementing a firewall technology limiting communication between systems behind the web server.

I agree with MacVittie that just because it is how something has historically been done is not justification for continuing to do it that way.  But I also don’t see this as a reason to run a network without a firewall; just a discussion about where to implement them.  In all cases, regardless of where the firewall is implemented, the key to ensuring it is an effective security control is to effectively manage it.

About Jody Brazil

As Founder and CEO of FireMon, Jody Brazil is a seasoned entrepreneur with more than two decades of executive management experience and deep domain expertise in all aspects of networking, including network security design, network security assessment, and security product implementation. Before joining FireMon in 2004, Brazil spent eight years at FishNet Security, serving as Chief Technology Officer, where he was responsible for providing direction for solutions to their customers. Previously, he was president and founder of Beta Technologies, a Network Services and Internet Application Development company. A few of Brazil’s major accomplishments include his implementation of the first load balanced deployment of Check Point firewall software in 1997. A year later he engineered the security solution that allowed, for the first time, the transfer of criminal history data over the Internet as approved by the FBI. Brazil then released the first ever graphical firewall policy change view in 2001 and the first ever firewall rule usage analysis application in 2004.

3 thoughts on “Firewalls in the Data Center…security or bottleneck?

  1. Lori MacVittie

    Absolutely! It’s the services and how they are managed, not necessarily the physical solution, that’s important. the services still need to exist – the question is where best (and for what services) to do that without compromising other operational risks.


  2. Justin Jocewicz

    What I would like to see are the numbers from Arbor Networks showing the following statistics of companies who do not deploy firewalls in front of their web services DMZ:

    1) How much faster the attack happens
    2) How much more data was lost
    3) How much longer was the downtime to the company

    Then, I would like for Arbor Networks to ask the CEO of a company whose now unprotected public servers become compromised whether it was worth it or not.

    It is easy to blame a firewall as a bottleneck or as being unreliable. Maybe even not that secure when you aren’t seeing what it is doing on a daily basis.

    The truth is that Arbor wants to sell their devices and services for DDos protection. They are good at what they do, but having DDos protection is not taking a holistic look at securing a web services DMZ in a datacenter environment.


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