ci sono riuscito con l'aiuto del forum, posto il codice c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

class MyClient
{
public static void Main()
{
//scelgo l'host
IPHostEntry IPHost = Dns.Resolve("localhost");
Console.WriteLine(IPHost.HostName);
string []aliases = IPHost.Aliases;

IPAddress[] addr = IPHost.AddressList;
Console.WriteLine(addr[0]);
EndPoint ep = new IPEndPoint(addr[0],80);

Socket sock = new Socket(AddressFamily.InterNetwork,SocketType.Strea m,ProtocolType.Tcp);

sock.Connect(ep);
if(sock.Connected)
Console.WriteLine("OK");
Encoding ASCII = Encoding.ASCII;
string Get=@"&user=gg";

string protocol="HTTP/1.0" ;
string br="\r\n" ;
string target="/phpinfo.php" ;
string host="localhost";


string req_body="" ;

req_body+="&user=giugioxxxxxx" ;



string headers="POST "+target+" "+protocol+br ;
headers+="Content-Type: application/x-www-form-urlencoded"+br ;
headers+="Content-Length: "+req_body.Length+br+br ;


Byte[] ByteGet = ASCII.GetBytes(headers+req_body);
Byte[] RecvBytes = new Byte[2256];
sock.Send(ByteGet, ByteGet.Length, 0);
Int32 bytes = sock.Receive(RecvBytes,0, RecvBytes.Length, 0);
string strRetPage="";
strRetPage = ASCII.GetString(RecvBytes, 0,RecvBytes.Length);
Console.WriteLine(strRetPage );

strRetPage = null;
strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes);
while (bytes > 0)
{
bytes = sock.Receive(RecvBytes,0, RecvBytes.Length,SocketFlags.Peek);
strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes);
Console.WriteLine(strRetPage );
}
sock.Shutdown(SocketShutdown.Both);
sock.Close();
}
}