How to Test Your Mac Network
After you’ve set up your Mac wireless network and all your equipment, you need to make sure that everything works as it should. Fortunately, testing your AirPort network is as easy as opening Safari and seeing whether you can browse.
If you run into problems, click the signal strength icon in the menu bar and make sure that an AirPort network or other router is in range.
If you’re still having trouble, open System Preferences under the Apple menu and choose Network. Click the Assist Me button and then click Diagnostics in the dialog box that appears. You can check the status of AirPort and Network Settings, your ISP, and so on.
If you live in an apartment building or are close to your neighbors, their routers may show up on your Mac’s list. In some cases, your neighbors’ signal will be so strong that you could piggyback on their setup. If you didn’t implement your security settings (requiring robust passwords) when you set up your Wi-Fi network, keep in mind that your neighbors can also piggyback on your network, compromising security.