c#获取本机内网和外网IP

//获取内网IP
private string GetInternalIP()
{
    IPHostEntry host;
    string localIP = "?";
    host = Dns.GetHostEntry(Dns.GetHostName());
    foreach (IPAddress ip in host.AddressList)
    {
        if (ip.AddressFamily.ToString() == "InterNetwork")
        {
            localIP = ip.ToString();
            break;
        }
    }
    return localIP;
}

//获取外网IP
private string GetExternalIP()
{
    string direction = "";
    WebRequest request = WebRequest.Create("http://checkip.dyndns.org/");
    using (WebResponse response = request.GetResponse())
    using (StreamReader stream = new StreamReader(response.GetResponseStream()))
    {
        direction = stream.ReadToEnd();
    }
    int first = direction.IndexOf("Address:") + 9;
    int last = direction.LastIndexOf("</body>");
    direction = direction.Substring(first, last - first);
    return direction;
}