Maybe a proxy problem ? If you use a proxy server to connect to the internet, try to set the Proxy member of WebRequest. example

private string readHtmlPage(string url)
{
string _result;
WebResponse objResponse;

WebProxy myProxy = new WebProxy( <hostname/ip>, <port number> );
// if your proxy requires authentication add
// myProxy.Credentials = new NetworkCredentials( <username>, <password> \[, <domain>\] )

WebRequest objRequest = System.Net.HttpWebRequest.Create(url);
// apply proxy to web request
objRequest.Proxy = myProxy;

objResponse = objRequest.GetResponse();
using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()) )
{
    \_result = sr.ReadToEnd();
    // Close and clean up the StreamReader
    sr.Close();
}
return \_result;

}

Maybe this helps ;)

It depends if the chat app is using remoting. Take a look here: http://www.ingorammer.com/Software/OpenSourceRemoting/BiDirTcpChannel.html

you need to have a bidirectional remoting channel. I think the standard .net channel classes are only unidirectional. Search the web for "bidirectional remoting channel". I've seen such a tutorial but I can't remember where it was.

use SNMP to communicate with the router. but I haven't done something like this in c# til now.