In the first Snort Report we created a "configuration file" called snortconf.test that contained a single ICMP rule. Invoking that configuration file via the -c switch put Snort in intrusion detection mode. In production, Snort packages a snort.conf configuration file in the etc/ directory. This directory will not appear in the /usr/local/snort-220.127.116.11/ directory, but it will be in the /usr/local/src/snort-18.104.22.168/etc/ directory. The snort.conf file is the place where a variety of configuration options can be set, and it is the preferred place to control Snort's operation.
Here I will start with a blank configuration file, called snort-22.214.171.124.20dec06a.conf, and add values as I describe their function. In this article I address only those functions enabled by default in snort.conf. I'll address the functions disabled by default in future articles.
Snort: Understanding the configuration file
Introduction: Upgrade to Snort 126.96.36.199
The snort.conf file
Defining IP ranges of interest
Defining ports of interest
About the author
Richard Bejtlich is founder of TaoSecurity, author of several books on network security monitoring, including Extrusion Detection: Security Monitoring for Internal Intrusions, and operator of the TaoSecurity blog.