Querying Address Records using Fail over DNS servers

The following example uses the DnsQuery object to query microsoft.com for Address records using fail over DNS servers. aspNetDns has the capability to use multiple DNS servers for fail over functionality. If a connection to one DNS server fails, or quits responding, aspNetDns will automatically move to the next DNS server. In this example we use 3 DNS servers for failover (each DNS server is separated by a semi-colon): 127.0.0.1;207.46.138.20;143.236.12.13

[C#]

using System;
using aspNetDns;
using aspNetDns.Records;
namespace ConsoleApplication1
{
	class Class1
	{
		[STAThread]
		static void Main(string[] args)
		{

			DnsQuery dns = new DnsQuery( "127.0.0.1;207.46.138.20;143.236.12.13" );
			string LookupRecord = "microsoft.com";
			ResourceRecord[] records = dns.GetDnsRecords( DnsQueryType.A, LookupRecord );
			if( records.Length > 0 )
			{
				for( int i=0;i<records.Length;i++)
				{
					Console.WriteLine( "Address Record: " + records[i].AnswerString );
				}

			}
			else
			{
				Console.WriteLine( "No address records were found.");
			}


			Console.WriteLine( "done.");
			Console.ReadLine();
		}
	}
}


 

 

[VB.NET]

Imports aspNetDns
Imports aspNetDns.Records
Module Module1

    Sub Main(ByVal args() As String)

        Dim dns As New DnsQuery( "127.0.0.1;207.46.138.20;143.236.12.13" )
        Dim LookupRecord As String = "microsoft.com"
        Dim records As ResourceRecord() = dns.GetDnsRecords(DnsQueryType.A, LookupRecord)
        If records.Length > 0 Then
            Dim i As Integer
            For i = 0 To records.Length - 1
                Console.WriteLine("Address Record: " + records(i).AnswerString)
            Next i

        Else
            Console.WriteLine("No address records were found.")
        End If

        Console.WriteLine("done.")
        Console.ReadLine()

    End Sub 'Main

End Module