Check out the new USENIX Web site.

USENIX Home . About USENIX . Events . membership . Publications . Students
19th Large Installation System Administration Conference—Abstract

Pp. 103–112 of the Proceedings

An Open Source Solution for Testing NAT'd and Nested iptables Firewalls

Robert Marmorstein and Phil Kearns, College of William and Mary


As firewalls have increased in power and flexibility, the complexity of configuring them correctly has grown significantly. An error in the firewall configuration can compromise the security of the system or interfere with normal network activity. The chance of an error increases when coordinating multiple firewalls, because the interaction between filters may hide errors more easily noticed on a single firewall. Firewalls on many networks use network address translation, which further increases the complexity of the firewall policy and creates additional opportunities for errors. Because errors in the firewall configuration are often extremely costly in time and security, system administrators need tools for verifying and debugging their firewall policy. ITVal is a tool for analyzing iptables-based firewalls that provides a plain English query language for simple firewall analysis. In this work, we describe extensions to ITVal that allow it to process network address translation rules and analyze multiple firewalls connected sequentially.
  • View the full text of this paper in HTML and PDF.
    Click here if you have forgotten your password Until December 2006, you will need your USENIX membership identification in order to access the full papers. The Proceedings are published as a collective work, © 2005 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.

  • If you need the latest Adobe Acrobat Reader, you can download it from Adobe's site.
To become a USENIX Member, please see our Membership Information.

?Need help? Use our Contacts page.

Last changed: 8 Dec. 2005 rc
Technical Program
LISA '05 Home