There is a need for a systematic approach to verifying router configurations before they are deployed. In this work, we develop a static analysis framework for configuration checking and use it in the design of rcc, a "router configuration checker." rcc takes as input a set of router configurations and flags anomalies and errors based on a set of well-defined correctness conditions. We have used rcc to check BGP configurations from nine operational networks, testing nearly 700 real-world router configurations in the process. Every network we analyzed had configuration errors, some of which were potentially serious and had previously gone unnoticed. Our analysis framework and results also suggest ways in which BGP and configuration languages should be improved. rcc has also been downloaded by 30 network operators to date.

In this talk, I will:

• Provide a survey of the BGP-related problems that have been discussed on the NANOG mailing list over the last 10 years
• Discuss the framework we have developed for static analysis of BGP configurations.
• Present a summary of the configuration errors we found in the ASes we have surveyed thus far.
• Ask for more cooperation from the NANOG community. In particular, we would greatly benefit from having more people test out the tool, suggest additional features and checks, and let us know the types of errors that they have turned up in their configurations.