Laptop users often connect to public Wi-Fi services. Many people are concerned for their privacy on such connections and wonder if their activities can be traced to their own identities or machines. Others are concerned about possible interception of data. There are two feasible ways of identifying a user on an Internet connection: MAC address and IP address.
An IP (Internet protocol) address is a unique number assigned to users of a wireless network. For example, if you connect to a public Wi-Fi service, your IP address will be the same as everyone else's on that connection.
IP addresses only identify the person or organization that hosts the connection. A person cannot simply look up your name and address using your IP address. The best she will get is your approximate geographic location and Internet service provider. It is only possible to get an actual registrant's information by court order.
A MAC (media access control) address is a number assigned to network adapters. For example, if you join a public Wi-Fi network, your MAC address will (most likely) be different from another person's MAC address because you have a different wireless card.
MAC addresses are supposed to be unique, but manufacturers can sometimes neglect to ensure that every device is assigned a different number. In addition, MAC addresses can be "spoofed" by computer programs. Therefore, a MAC address is not considered personally identifiable information. However, because your MAC address is static, wireless networks can track your connections and block your laptop.
To ensure privacy over a public Wi-Fi network, make sure you have enabled an Internet security suite with a firewall. Set any wireless settings to "public." Also, to be sure, do not enter any sensitive information over such a connection. Be aware that the connection host can intercept any data being sent over the connection.