Connection Approval

Connection approval is a way for the server to accept or deny connections based on some data sent by the client.

The way this is done is that the client (or initiating peer) adds a NetOutgoingMessage to its Connect call, like this:

NetOutgoingMessage approval = myClient.CreateMessage();
approval.Write("secret");

myClient.Connect(host, 14242, approval);

This will send the string "secret" as approval data. On the server you must first enable connection approval:

myConfig.EnableMessageType(NetIncomingMessageType.ConnectionApproval);

... then, in your message loop, receive the appropriate message, read the data (and check other stuff, such as SenderConnection.RemoteEndpoint to block certain IPs.

switch (inc.MessageType)
{
    case NetIncomingMessageType.ConnectionApproval:
            string s = inc.ReadString();
            if (s == "secret")
                inc.SenderConnection.Approve();
            else
                inc.SenderConnection.Deny();