System.Net;

string host = "www.yahoo.co.jp";

try 
{
	IPHostEntry hostInfo = Dns.GetHostByName(host);

	for(int index=0; index < hostInfo.AddressList.Length; index++)
	{
		Console.WriteLine(hostInfo.AddressList[index]);
	}
}
catch(Exception e)
{
	Console.WriteLine(e.Message);
}