DNS NsLookup using VBScript

The Domain Name System (DNS) is the method by which Internet addresses in mnemonic form - such as www.activexperts.com - are converted into the equivalent numeric IP address such as 212.97.55.136. To the user and application process this translation is a service provided either by the local host or from a remote host via the Internet. The DNS server (or resolver) may communicate with other Internet DNS servers if it cannot translate the address itself.
DNS names are constructed hierarchically. The highest level of the hierarchy is the last component or label of the DNS address. Labels can be up to 63 characters long and are not case sensitive. A maximum length of 255 characters is allowed. Labels must start with a letter and can only consist of letters, digits and hyphens.

Nslookup is a popular program for UNIX, LINUX and Windows to query Internet domain name servers. It allows the user to query name servers for information about various hosts and domains or to print a list of hosts in a domain.

ActiveSocket provides an easy-to-use development/scripting interface to use the same operations as NsLookup, through the DnsServer class. By using ActiveSocket, you can very easily create or enhance Windows applications/scripts with DNS lookup features.

ActiveSocket features the following: ICMP, HTTP and HTTPs (supporting for proxy servers, secure web sites), FTP, DNS, Telnet, NTP time protocol, RSH remote shell script interface, SNMP (Simple Network Management Protcol), SNMP Traps, Sockets, WOL (Wake-On-LAN), and more.

Step 1: Download and install the ActiveSocket Toolkit

Download ActiveSocket from the ActiveXperts Download Site and start the installation. The installation guides you through the installation process.

Step 2: Create a new script

Create a new script using your favorite editor. You can simply use notepad. However, a VBScript editor is recommended, so you can browse through objects, objects properties and object functions.

You're now able to write a more advanced script to communicate using the ActiveSocket Toolkit.

Step 3: Create the ActiveSocket object in VBScript

Create a new VBScript file called DEMO.VBS. It is recommended to insert the following line on top of your code:

   Option Explicit

This statement requires that all variable names be defined (with the Dim statement), to avoid simple typos that can cause incredible headaches and long debugging sessions for something that should have never happened.

Now, declare the ActiveSocket object(s):

   Dim objDnsServer

Create the ActiveSocket object(s) like this:

   Set objDnsServer      = CreateObject( "ActiveXperts.DnsServer" )

Now, add the following lines to the file to have your fist ActiveSocket VBScript program:

   WScript.Echo "Version: " & objDnsServer.Version
   WScript.Echo "Expiration Date: " & objDnsServer.ExpirationDate

Step 4: Execute a DNS lookup query

You can now connect to a (remote) DNS server and execute a query.
The following VBScript code shows how to loolup a hostname (A-record) and print its IP address:

Option Explicit

Dim objDnsServer, objDnsRecord, objConstants

Set objDnsServer = CreateObject ( "ActiveXperts.DnsServer")
Set objConstants = CreateObject ( "ActiveXperts.ASConstants")

objDnsServer.Server     = "ns1.interstroom.nl"
   
objDnsServer.Lookup "www.activexperts.com", objConstants.asDNS_TYPE_ANY
If ( objDnsServer.LastError <> 0 ) Then
    WScript.Echo "ERROR #" & objDnsServer.LastError & " (" & objDnsServer.GetErrorDescription (objDnsServer.LastError ) & ")"
    WScript.Quit
End If

If ( objDnsServer.IsAuthoritative = True ) Then
    WScript.Echo "Server is an authority for this domain"
Else
    WScript.Echo "Server is not an authority for this domain"
End If

WScript.Echo

Set objDnsRecord = objDnsServer.GetFirstRecord
On Error Resume Next
	
While ( objDnsServer.LastError = 0 )

    Select Case objDnsRecord.Type 
      Case objConstants.asDNS_TYPE_A
        WScript.Echo "Type             : A"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "IPv4 Address     : " & objDnsRecord.Address
      Case objConstants.asDNS_TYPE_AAAA
        WScript.Echo "Type             : AAAA"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "IPv6 Address     : " & objDnsRecord.Address
      Case objConstants.asDNS_TYPE_CNAME
        WScript.Echo "Type             : CNAME"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "Alias            : " & objDnsRecord.Address
      Case objConstants.asDNS_TYPE_MX 
        WScript.Echo "Type             : MX"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "Preference       : " & objDnsRecord.Preference
        WScript.Echo "Mail Exchange    : " & objDnsRecord.MailExchange
      Case objConstants.asDNS_TYPE_NS
        WScript.Echo "Type             : NS"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "Name Server      : " & objDnsRecord.NameServer
      Case objConstants.asDNS_TYPE_PTR
        WScript.Echo "Type             : PTR"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "Host             : " & objDnsRecord.Address
      Case objConstants.asDNS_TYPE_SOA
        WScript.Echo "Type             : SOA"
        WScript.Echo "Name             : " & objDnsRecord.Name
        WScript.Echo "Name Server      : " & objDnsRecord.NameServer
        WScript.Echo "MailBox          : " & objDnsRecord.MailBox
        WScript.Echo "Serial           : " & objDnsRecord.SerialNumber
        WScript.Echo "Refresh          : " & objDnsRecord.RefreshInterval
        WScript.Echo "Retry Interval   : " & objDnsRecord.RetryInterval
        WScript.Echo "Expiration Limit : " & objDnsRecord.ExpirationLimit
        WScript.Echo "Minimum TTL      : " & objDnsRecord.MinimumTTL
    End Select
	
    WScript.Echo "TTL              : " & objDnsRecord.TTL
    WScript.Echo
		
    Set objDnsRecord = objDnsServer.GetNextRecord

Wend

There are many working samples included with the product. You can also find them on the ActiveXperts FTP site: ftp.activexperts-labs.com/samples/asocket.

The ActiveSocket tool is a Network Communications ActiveX software component (SDK). This control supports SNMP, SMTP, POP3, Telnet, TCP, NTP, RSH, HTTP, HTTPs, FTP, DNS, ICMP and more, and can be used by any Windows development platform, including Visual Basic .NET, Visual CSharp .NET, ASP .NET (VB,CS), ASP, Visual Basic, Visual Studio/Visual C++, Delphi, PHP, ColdFusion, HTML, VBScript and any other ActiveX/COM compliant platform. The ActiveSocket Toolkit is an ActiveXperts Software B.V. Product.