How we can handle application_error issue in IIS server with IP address?

void Application_Error(object sender, EventArgs e)
    {
        // Code that runs when an unhandled error occurs
        try
        {
            Exception exc = Server.GetLastError().GetBaseException();
            if (exc.GetType() == typeof(HttpException))
            {
                // The Complete Error Handling Example generates
                // some errors using URLs with "NoCatch" in them;
                // ignore these here to simulate what would happen
                // if a global.asax handler were not implemented.
                if (exc.Message.Contains("NoCatch") || exc.Message.Contains("maxUrlLength"))
                    return;

                //Redirect HTTP errors to HttpError page
                //Server.Transfer("HttpErrorPage.aspx");
            }
            //ExceptionUtility.LogException(exc, "");
            SendExcepToDB(exc);
            Server.ClearError();
        }
        catch( Exception ecv)
        {
            throw ecv;
        }
    }

<configuration>
  <connectionstrings>
  
  <system.web>
    <compilation debug="true" targetframework="4.5">
    <customerrors mode="On">     
    
  
 
    <system.webserver>
      <httperrors existingresponse="PassThrough">
        <defaultdocument>
            <files>
                <clear>
                <add value="Default.aspx">
                <add value="Default.htm">
                <add value="Default.asp">
                <add value="index.htm">
                <add value="index.html">
                <add value="iisstart.htm">