TcpClient Memory Leak

Question

I have created a server that works perfectly. However when I decided to test it against a DDoS attack I found a major memory leak. The code below, will fill up RAM (when DDoS'd) and eventually crash my computer. I have tried to implement counter-measures however the memory leak still exists. My current code for listening is:

TcpClient connection = server.AcceptTcpClient();
if (!IpByConnection.ContainsKey(connection.Client.RemoteEndPoint.ToString().Split(':')[0])) {

    IpByConnection.Add(connection.Client.RemoteEndPoint.ToString().Split(':')[0], connection);

    CipherNetwork network = new CipherNetwork(connection);
    network.ListenOnDifferentThread(true);
    network.DisconnectOnError(true);
    network.StartListening();

    TotalConnections += 1;

} else {
    connection.Close();
}

How would I fix this memory leak ?

EDIT: I forgot to mention, the method is run on a separate thread.
EDIT 2: I have tried setting it to null, disposing it and both.

Answer 1

I was unable to find a direct solution however I managed to solve the problem by limiting each connection 5 per IP, using A Dictionary to store the connected users and remove them once they disconnected.