using System.Management;

string stringMAC = "";
string stringIP = "";
ManagementClass MC = new ManagementClass "Win32_NetworkAdapterConfiguration");
ManagementObjectCollection MOC= MC.GetInstances();

foreach(ManagementObject MO in MOC)
{
if ((bool)MO["IPEnabled"] == true)
{
stringMAC += MO["MACAddress"].ToString();
TextMAC.Text = stringMAC.ToString();
string[] IPAddresses = (string[]) MO["IPAddress"];
if(IPAddresses.Length > 0)
stringIP = IPAddresses[0];
TextIP.Text = stringIP.ToString();
}
}

获得客户端ip地址请参考:http://happysnail.org/index.php/archives/367