Recommendations for DDOS detection software?

[major at mhtx.net (Major Hayden)]

Hello there,

Does anyone have any recommendations for DDOS detection software which runs on Linux?  We're currently testing out Network Probe:

  http://objectplanet.com/probe/

We've written some custom "top talkers" scripts to analyze tcpdump data, but we'd like a more elegant solution with some basic alarm functionality.

Thanks!

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Major Hayden