Firewalk X lets you work with OS X's firewall

Since Mac OS X is running Unix at its core, it offers more powerful Internet services than the traditional Mac operating system. You may want to check out Firewalk X, a configuration and maintenance utility for Mac OS X’s built-in firewall.

Firewalk X can create rules for TCP, UDP, and ICMP protocols and can specify ranges of IP addresses and ports including origination and destination ports. It offers a configurable automatic port value inserter to help with rule setup and system setup for firewall activation at system startup.

You can view rules that are currently installed in the firewall for confirmation. Firewalk X also supports:

Logging of user defined firewall events and notification of new events;

Saving, importing and exporting of rules sets;

A Watch Mode to help with firewall setup;

The ability to preserve NAT settings for most NAT configurations;

A “dockling” that allows switching rule sets on the fly

A smaller, compressed main interface to preserve screen real estate;

Setup Assistants to aid novices with firewall setup

A Firewalk X Repair Kit application that can fix possible problems with Firewalk X and the firewall.

Firewalk X is US$12. It requires Mac OS 10.0.3 or higher. You can download a copy (a 1.1 M file) from author Mike Vannorsdel’s Web site.