The term Adaptive Firewall can mean a lot of things to a lot of people. In Mac OS X Server it means that if you attempt to logon with an inappropriate password 10 times that a dynamic rule will be created blocking access for the computer that access was attempted from for 15 minutes. After 15 minutes the dynamic rule will be removed from the server. To see the number of Dynamic Rules running on a server, look at the Firewall services Overview tab, or Active Rules. There’s not a timer but it’s pretty easy to see which IPs are blocked. I’ve found it doesn’t always clear out after 15 minutes. If not, then create a new rule and let ipfw flush the rules and any Dynamic Rules should disappear.