Ethernet Network Settings on Your MacBook

By Mark L. Chambers from MacBook All-in-One For Dummies, 2nd Edition

When you select Ethernet from the list of connection types on your MacBook's Network pane, the Status pane shows your connection information. Because most networks have a DHCP server to provide automatic settings, you probably don’t have to change anything; Lion does a good job at making introductions automatic between your MacBook and both a local network and the Internet.

Notice the very attractive Assist Me . . . button at the bottom of the Network pane? It’s there for a very good reason: Click it, and Lion launches a network connection and troubleshooting assistant that guides you step-by-step.

If your ISP doesn’t provide you with instructions on setting up your Internet connection — or that oh-so-smart Mr. Network Administrator is too busy to help connect your MacBook to your office network — use the network assistant to do the job yourself!

Need to make manual changes to your network settings? Click the Advanced button (it’s like opening the hood on your car). The tabs on the Advanced sheet include

TCP/IP: These settings are provided either automatically (by using Dynamic Host Configuration Protocol [DHCP]) or manually (by using settings provided by your network administrator).
DNS: The settings that you enter here specify the DNS servers and search domains used by your ISP. Typically, any changes you make here are requested by your ISP or your network administrator. Click the Add buttons (with the plus signs) to add a new DNS server address or search domain.
WINS: Dating back a few years, WINS is a name server required for computers running NetBIOS (practically dinosaurs in the computer timeline), and likely only those computers running a version of Windows older than Windows 2000. If that sounds like gobbledygook to you, you need to enter something on this tab only if instructed to do so by your network administrator.
802.1X: This tab controls which wireless networking security protocols that you may need to connect to a third-party wireless base station or access point. Click the Enable Automatic Connection check box when making a wireless connection with an Apple Airport Extreme base station or Time Capsule backup unit.
Proxies: Network proxy servers are used as part of a firewall configuration to help keep your network secure, but in most cases, changing them can cause you to lose Internet functionality if you enter the wrong settings.

Most folks using a telephone modem, cable modem, or digital subscriber line (DSL) connection should leave these settings alone. Enable and change these settings only at the request of your network administrator, who should supply you the location of a PAC file to automate the process.

If you’ve enabled your Mac OS X firewall and you use FTP to transfer files, enable the Passive FTP Mode check box on the Proxies pane. I recommend that you enable this setting to allow downloading from some Web pages as well.
Hardware: From this pane, you can configure the settings for your Ethernet network interface card. Leave the Configure pop-up menu set to Automatically (unless specifically told to set things manually by your system administrator or that nice person from Apple tech support).