has released IPNetSentryX 1.0, an Internet firewall application for Mac OS X.
Like conventional firewalls, it can define hierarchial firewall rules with those rules being based on IP addresses, ports and protocols (services). However, IPNetSentryX also lets you base rules on the content of incoming datagrams in order to do thing such as detect worms. Additionally, it lets you define which actions to take when rules are met. For instance, you could block an intruder, have an alert go off during an intrusion, send an e-mail message pertaining to the intrusion, run a designated AppleScript, or any combination of these actions.
IPNetSentryX costs US$40, which includes a free registration for IPNetSentry Classic. Registered users of IPNetSentryClassic can upgrade to the Mac OS X version for $20.