Are two network firewalls better than one?

Our network currently has two firewall systems: Fortinet's FortiGate and Cisco's PIX Firewall. To reduce processing delays, I suggested having one firewall, instead of both devices. What are the security advantages of having multiple firewalls from different vendors?

You raise a few interesting issues in your question. First, your underlying assumption is that the two firewalls are introducing a noticeable latency into your network. Generally speaking, when using modern firewalls that have capacity suitable for a modern enterprise network, there shouldn't be any significant delay, even when chaining two firewalls together. If you're experiencing a delay, it's probably a sign that one or both firewalls can't keep up with bandwidth requirements, hence it may be time to upgrade to a higher-capacity model.

Next, consider the placement of the firewalls. Are they both directly connected to each other with nothing else in between? If that's the case, consider using a different firewall topology that will get the most out of the two firewalls. For more information on arrangements, read my article

    Requires Free Membership to View

Placing systems in a firewall topology. If the firewalls aren't directly connected, make sure that they're not already part of a multi-homed topology implementation.

If there's no business case for redundant firewalls, it might be worthwhile to decommission one of them. Rather than emphasizing performance reasons, I'd cite the hassle and management overhead of maintaining two different systems. Rule changes must be made on both devices separately, effectively doubling administration time. If you're interested in achieving redundancy to protect against a hardware failure, however, consider using two of the same device in a high-availability deployment so that if one firewall fails, the other takes over.

This was first published in February 2009

There are Comments. Add yours.

TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.