Snort 3.0 Pass Rules

[jarose0010]

Is there a way to implement pass rules in Snort 3.0 in FTD? 

It appears the action of pass is available in Snort 3.0 but I am not able to find any Cisco documentation on how to implement it. 

Creating a pass rule and then setting it to Action = Alert in the gui seems counterintuitive to me. 

Thank you in advance,

Jimmy

[Divya Jain]

Hello Jimmy,
You can refer to this guide to understand rule actions : https://www.cisco.com/c/en/us/td/docs/security/firepower/70/snort3/config-guide/snort3-configuration-guide-v70/tuning-intrusion-policies.html#ID-2237-0000063d_snort3
to edit poilcy : https://www.cisco.com/c/en/us/td/docs/security/firepower/70/snort3/config-guide/snort3-configuration-guide-v70/getting-started-intrusion.html#ID-2231-0000011a

Just to explain actions :

Available Snort 3 rule actions depend on the software release. Release 7.1 introduced additional rule actions. Snort 3 rule actions

Block: Generates event, drops matching packet and also blocks further traffic in this connection
Alert: Generates only event for matching packet, does not drop packet or connection.
Disable: Rule is not active in this policy.
Reject: Generates event, drops matching packet, blocks further traffic in this connection and sends TCP reset or ICMP port unreachable to source and destination hosts
Rewrite: Generates event and overwrites packet contents based on the replace option in the rule.
Pass: No event generated, allows packet to pass without further evaluation by any subsequent Snort rules.
Drop: Generates event, drops matching packet and does not block further traffic in this connection.

Now if you are creating a pass rule, your actions has to be pass to and this means you are trusting the traffic and do not want it be evaluated.

Sample attached :

Hope this helps.

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[ivanradevradev_]

Hi, 

After Firepower 7.2 thinks had changed and now are more confusing then ever, because different versions are having different dictionary. 

 
https://www.cisco.com/c/en/us/td/docs/security/secure-firewall/management-center/snort/720/snort3-configuration-guide-v72/getting-started-intrusion.html

[ivanradevradev_]

Anyway, use the official snort guide and import your rules as .txt to the FMC. 
And yes, pass rules to be activated should be in "alert" state , but they would not alert because are pass rules. "Clear" somehow? 
https://docs.snort.org/rules/headers/actions