Keychain Access and Network Utility Port Scan is nothing to play with. A system administrator I know was testing his own network when he mistakenly transposed two numbers in an IP address and scanned a completely different system. The administrator of the scanned system took offense at the possible security breach and sent a harshly worded letter of warning to my friend and his ISP. 188 For the most part, ordinary users don't need to use Network Utility. It's provided as a tool for network administrators to test computers that that might be having trouble on the network. For those inter- ested in giving the application a test drive, you'll see a real-world example in Hour 23. Summary In this hour, we considered some of Mac OS X's network helpers. Keychain serves as a storage place for all the passwords and important data that a person needs close at hand. The functions located under Network Utility are less-commonly needed, but are equally easy to use. Several of the most important functions are discussed in upcoming sections. Q&A Q1: A1: Are keychains really secure? The information stored for Keychain Access is encrypted, which makes it very difficult for someone to break into your computer and steal what's stored there. However, as one newsgroup contributor cautions, "As with all mathematical encryption, cracking is only really a matter of how hard you try to solve the equation." Also, if the passwords to access your keychains can be guessed, the rest