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Next: Replacing Packets with Snort Up: Inline Mode Previous: Snort Inline Rule Application   Contents


New STREAM4 Options for Use with Snort Inline

When using Snort Inline, you can use two additional stream4 options:

  • enforce_state drop

    Adding drop to the enforce_state option causes Snort to drop TCP packets that are not associated with an existing TCP session, and that are not valid TCP initiators.

  • midstream_drop_alerts (no arguments)

    By default, when running in inline mode, Snort will silently drop any packets that are matched against a drop rule and considered to be part of a midstream session, instead of logging the alert as usual. This is to mitigate stick/snot type attacks when the user hasn't enabled the enforce_state option. If you want to log these drops, enable this option. Note that by enabling this option, you have opened yourself up to stick/snot-type attacks if you haven't also used the enforce_state option.

  • disable_session_blocking (no arguments)

    By default, when running in inline mode, Snort will block all traffic on a TCP session after it is told to drop a non-stateless packet on that session. Enable this option if you don't want Snort to exhibit this default behavior.

For more information about Stream4, see Section [*].

next up previous contents
Next: Replacing Packets with Snort Up: Inline Mode Previous: Snort Inline Rule Application   Contents
Steven Sturges 2006-12-08
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