CSDNS



Click here for a larger image.

Environment: VS7, C#, .NET

This program is an example of using the DNS class to resolve host names to IP addresses and, where available, resolves host names from IP addresses. The methods for doing this are similar to the sockets functions gethostbyname and gethostbyaddr. Not all IP addresses resolve into host names; it depends on the DNS server, which may or may not have a reverse mapping defined. There also are asynchronous methods for doing the same functions. There even is a method, Dns.Resolve, that determines whether an IP address or host name is used and calls the appropriate method.

//-------------------------------------------------------
private void HostNameButtonClick(object sender,
                                 System.EventArgs e)
{
  m_status.Text = "Trying....";
  m_status.Update();
try
{
  IPHostEntry hostInfo = Dns.GetHostByName(m_host_name.Text);
  m_ip_address.Text    = hostInfo.AddressList[0].ToString();
  m_status.Text        = "ok";
}
catch (Exception excpt)
{
  m_status.Text = excpt.Message;
  m_ip_address.Text = "";
}
MessageBeep(1000);
}
//-------------------------------------------------------
private void IPAddressButtonClick(object sender,
                                  System.EventArgs e)
{
  IPAddress ipaddr = IPAddress.Parse(m_ip_address.Text);
  m_status.Text    = "Trying....";
  m_status.Update();
try
{
  IPHostEntry hostInfo = Dns.GetHostByAddress (ipaddr);
  m_host_name.Text     = hostInfo.HostName;
  m_status.Text        = "ok";
}
catch (Exception excpt)
{
  m_status.Text    = excpt.Message;
  m_host_name.Text = "";
}
  MessageBeep(1000);
}
//------------------------------------------------------
private void ResolveButtonClick(object sender,
                                System.EventArgs e)
{
  m_status.Text = "Trying....";
  m_status.Update();
try
{
  IPHostEntry hostInfo = Dns.Resolve(m_resolve_text.Text);
  m_ip_address.Text    = hostInfo.AddressList[0].ToString();
  m_host_name.Text     = hostInfo.HostName;
  m_status.Text        = "ok";
}
catch (Exception excpt)
{
  m_status.Text = excpt.Message;
  m_ip_address.Text = "";
}
  MessageBeep(1000);
}
//------------------------------------------------------

Downloads

Download demo project - 20 Kb


Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Live Event Date: May 18, 2015 @ 1:00 p.m. ET / 10:00 a.m. PT While the idea of using facial and or gesture recognitions to create a modern, intuitive game seems attractive, some developers may want to leverage Unity 3D as a way to accelerate their development. There are many different ways in which Intel and Unity Technologies have been working together to helps speed the develop of games with the Intel® RealSense™ SDK (Software Developer Kit), so come hear from a panel of experts on what we've done …

  • The advent of compute accelerators, special purpose coprocessors that significantly improve the performance of traditional host-based central processing unit (CPU) computations, represents a major transition in the tools available to achieve supercomputing power. This white paper presents Dell solution offerings and shows how they push the envelope of available solutions that bring immediate added value to HPC users in terms of integration, flexibility, and efficiency of hybrid compute solutions.

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date