Is there any way to configure the IPS module on an ASA firewall to only generate alerts (first phase of deployment). I am not sure about whether setting the 'event overwrite' option to 'Alert' and setting the RR to 0-100 will do the trick. I am currently thinking to also create a copy of the sig0 signatures and changing the pre-defined actions to Alert only but of course I would rather perform the first approach - Event Overwrite - if possible.
Yes you should be able to do this using event action overrides but you have to make sure you subtract all possible deny actions (deny packet,deny connection etc.) Another way could be to 'select all' for all the signatures then changes the action to Product Alert. Once the testing phase is finished, you can 'Select All' signatures and click on the 'Restore Defaults' button.
The copy procedure you are currently adopting is unnecessary.
Actually there are two different type of event action rules or manipulators, the first one adds actions and the other subtracts. The former is known as ' Event Action Overrides' and the latter is known as 'Event Action Filters'. have a look at this for more details:
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...