Using Ethernet

In most cases, Mac OS X correctly configures the Ethernet port to match the network configuration. However, in some cases, you may be required to manually override these settings. When Manually (Advanced) is chosen from the Configure pop-up menu in the Ethernet pane of Network preferences, you can specify the speed, duplex, and packet size used when communicating via the Ethernet port.

You may need to set a custom packet size when your broadband ISP adds packet overhead. Many DSL and cable modem ISPs add a few header bytes to packets, which can add a significant amount of packet traffic. If you are using the standard 1500-byte packet size, and your ISP adds six to eight bytes, the extra data must be sent in another packet. You may see performance improve if you reduce your packet size, because you will be sending fewer overflow packets.

NOTE

You should only change these settings if instructed to do so by your network administrator, or if you are certain that you can undo any changes. Incorrect settings can prevent your computer from communicating properly, and can interfere with network devices or other computers on the network.