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Error: The requested name is valid, but no data of the requested type was found when calling Dns GetHostByAddress

Track your visitors IP & Host Info, but make sure to catch any exceptions

Posted on 4/4/2007 7:50:01 AM in #ASP.NET

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In my previous article, How to track visitors to your site in ASP.NET & C#, I discussed how you can log the Host Info for each page visitor on your site using Dns.GetHostByAddress function.

One thing I did not stress out was the need to catch all exceptions from that method call. There are cases when this call:

string ipAddress = Dns.GetHostByAddress(ipAddress).HostName;

Will not succeed, and you will get the following Exception:

Server Error in '/' Application.

The requested name is valid, but no data of the requested type was found

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.Sockets.SocketException: The requested name is valid, but no data of the requested type was found

Source Error:

Line 21:             // Track Visitors

Line 22:             string ipAddress = IpAddress();

Line 23:             string hostName = Dns.GetHostByAddress(ipAddress).HostName;

From what I gathered, this happens with users connect from machines that are not listed on the Active Directory, or if their network settings is not "use NETBIOS over TCPIP". In all cases, not catching the exception on your side can mean your site is not going to work for these users.

To avoid this, I modified the code as follows:

try

{

hostName = Dns.GetHostByAddress(ipAddress).HostName;

}

catch (Exception ex)

{

Logger.EmailError(ex);

hostName += ex.Message;

}

This will let your site surfer in even if we can't resolve their machine host name.

Putting the above code, I got so many cases with users visiting my site generating this error, well at least now they can get in, where before, the web app would crash.

Thanks to my good friend John Sonmez who pointed out the error :)

Happy Programming!

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Jim Vazquez

Posted on 7/24/2012 12:41:37 PM

In my case, error was due Windows Firewall, after turn it off, everything worked like a charm

Sudarshan

Posted on 8/23/2011 3:42:13 AM

Server Error in '/Allcargoglobal.net' Application.
--------------------------------------------------------------------------------

The requested name is valid, but no data of the requested type was found
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.Sockets.SocketException: The requested name is valid, but no data of the requested type was found

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[SocketException (0x2afc): The requested name is valid, but no data of the requested type was found]
System.Net.Dns.GetHostByAddress(IPAddress address) +264
System.Net.Dns.GetHostByAddress(String address) +65
AGL.Dac.ITHelp.WebUserControl1.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\IThelp\UrlLinkList.ascx.cs:36
System.Web.UI.Control.OnLoad(EventArgs e) +67
System.Web.UI.Control.LoadRecursive() +35
System.Web.UI.Control.LoadRecursive() +98
System.Web.UI.Page.ProcessRequestMain() +750

--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:1.1.4322.2379; ASP.NET Version:1.1.4322.2379

The code is

System.Net.IPHostEntry host;
host = System.Net.Dns.GetHostByAddress(Request.ServerVariables["REMOTE_ADDR"]) ;
Label5.Text = host.HostName.Replace(".acmho.com","");
Label1.Text=DateTime.Now.ToLongTimeString().ToString();
UserName=Page.User.Identity.Name;
Connection oCon = new Connection();
Label3.Text = oCon.GetUserName("Get_UserName","@UserDomainName`",Page.User.Identity.Name+"`");
LinkList.DataSource=Connection.DataSet("Get_URLList","","");
LinkList.DataBind();
Datalist1.DataSource=Connection.DataSet("Get_SiteList","","");
Datalist1.DataBind();

I get the error when i click the link then it get's the above error message.

Prakash

Posted on 8/5/2011 1:22:48 AM

the requested name is valid but no data of the requested type was found

try
{