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Next: Using the Honeynet Snort Up: Inline Mode Previous: Installing Snort Inline   Contents

Running Snort Inline

First, you need to ensure that the ip_queue module is loaded. Then, you need to send traffic to Snort Inline using the QUEUE target. For example: 

iptables -A OUTPUT -p tcp --dport 80 -j QUEUE
sends all TCP traffic leaving the firewall going to port 80 to the QUEUE target. This is what sends the packet from kernel space to user space (Snort Inline). A quick way to get all outbound traffic going to the QUEUE is to use the rc.firewall script created and maintained by the Honeynet Project (http://www.honeynet.org/papers/honeynet/tools/) This script is well-documented and allows you to direct packets to Snort Inline by simply changing the QUEUE variable to yes.

Finally, start Snort Inline: 

snort_inline -QDc ../etc/drop.conf -l /var/log/snort

You can use the following command line options:

  • -Q - Gets packets from iptables.
  • -D - Runs Snort Inline in daemon mode. The process ID is stored at /var/run/snort_inline.pid
  • -c - Reads the following configuration file.
  • -l - Logs to the following directory.

Ideally, Snort Inline will be run using only its own drop.rules. If you want to use Snort for just alerting, a separate process should be running with its own rule set.

next up previous contents
Next: Using the Honeynet Snort Up: Inline Mode Previous: Installing Snort Inline   Contents
Steven Sturges 2006-12-08
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