//添加组件System.Management
using System.Management;
using System.Runtime.InteropServices;

[DllImport("Iphlpapi.dll")]
private static extern int SendARP(Int32 dest, Int32 host, ref Int64 mac, ref Int32 length);
[DllImport("Ws2_32.dll")]
private static extern Int32 inet_addr(string ip);

protected void Page_Load(object sender, EventArgs e)
{
try
{
string userip = Request.UserHostAddress;
Int32 ldest = inet_addr(userip); //目的地的ip
Int32 lhost = inet_addr(""); //本地服务器的ip
Int64 macinfo = new Int64();
Int32 len = 6;
int res = SendARP(ldest, 0, ref macinfo, ref len);
string mac_src = macinfo.ToString("X");
if (mac_src == "0")
{
if (userip == "127.0.0.1")
userinfo.Text = "正在访问Localhost!";
else
userinfo.Text = "欢迎来自IP为" + userip + "的朋友！";
return;
}
while (mac_src.Length < 12)
{
mac_src = mac_src.Insert(0, "0");
}
string mac_dest = "";
for (int i = 0; i < 11; i++)
{
if (0 == (i % 2))
mac_dest = mac_dest.Insert(0, mac_src.Substring(i, 2));
}
userinfo.Text = "欢迎来自IP为" + userip + ",MAC地址为" + mac_dest + "的朋友！";
}
catch (Exception err)
{
Response.Write(err.Message);
}
}