title: No reply on ping 224.0.0.1
body: <p>I am playing with multicast these days and I run into some odd things that I do not understand. </p>
  
  <p>I create a chat multicast clients and everything seems to work ok. After that I read some linux documentation and figured out that by pinging the 224.0.0.1 should return me reply from all nodes that joined to some multicast group. I tried that on xp and on win7 machine. The behavior is the same on both of them. It seems that my client only joins to the group I defined (224.0.19.1). It does not join the 224.0.0.1 group.</p>
  
  <p>From wireshark: 
  [source ip] 224.0.0.22  IGMPv3  54  Membership Report / Join group 224.0.19.1 for any sources</p>
  
  <p>And here is how i set my socket: </p>
  
  <pre><code>        IPEndPoint ipep = new IPEndPoint(IPAddress.Any, int.Parse(port));
  
          m_socket.Bind(ipep);
  
          IPAddress ip = IPAddress.Parse(mcastGroup);
  
          m_socket.SetSocketOption(
              SocketOptionLevel.IP, SocketOptionName.AddMembership, 
              new MulticastOption(ip, IPAddress.Any));
  </code></pre>
  
  <p>Then i checked in netsh: </p>
  
  <pre><code>C:\Users\user1&gt;netsh interface ip show joins
  
  Interface 1: Loopback Pseudo-Interface 1
  
  Scope       References  Last  Address
  ----------  ----------  ----  ---------------------------------
  0                    2  Yes   239.255.255.250
  
  Interface 11: LAN
  
  Scope       References  Last  Address
  ----------  ----------  ----  ---------------------------------
  0                    0  Yes   224.0.0.1
  0                    1  Yes   224.0.0.252
  0                    1  Yes   224.0.19.1
  0                    1  Yes   230.230.230.230
  0                    2  Yes   239.255.255.250
  
  Interface 15: Local Area Connection* 9
  
  Scope       References  Last  Address
  ----------  ----------  ----  ---------------------------------
  0                    0  Yes   224.0.0.1
  </code></pre>
  
  <p>And as you can notice there is no reference to the 224.0.0.1 address. 
  Of course I did turn off the firewall on both machines. </p>
  
  <p>Now the question is: Is this something not supported by windows? Not supported by .NET? Did I forget to implement something? I would appreciate any help. Thanx.</p>