Entry level question about adding custom rules. Snort won't start w/ rule.



  • I installed and setup snort Security 3.2.9.1 for my wan interface to just log alerts not blocking.
    I enabled the categories for the gpl2 list.

    https://doc.pfsense.org/index.php/Snort_rules

    So I went to custom rules drop down and adding the following:

    alert tcp any any -> any any ( msg:”DAT”; )

    When I add this snort stops working and I can start the process, but when i enable the interface it kills snort again.

    My alert may not be the correct syntax, but looking at a snort page on alerts it appears to be correct.
    https://www.snort.org/faq/readme-file_ips

    Anyone with experience think I just have bad syntax or did I add a custom rule in the wrong place or this could be an issue with the version of snort package I am running?



  • Your rule syntax is missing the CLASSIFICATION tag (uses the classtype keyword).  The Snort binary on pfSense wants that in a rule because of some customization done in the CSV output module.  If that section of the rule is missing, it causes problems.

    Bill