Recipe 13.7 Creating and Deleting Resource Records

13.7.1 Problem

You want to create and delete resource records.

13.7.2 Solution

13.7.2.1 Using a graphical user interface
  1. Open the DNS Management snap-in.

  2. If an entry for the DNS server you want to connect to does not exist, right-click on DNS in the left pane and select Connect to DNS Server. Select This computer or The following computer, enter the server you want to connect to (if applicable), and click OK.

  3. If you want to add or delete a record in a forward zone, expand the Forward Lookup Zone folder. If you want to add or delete a record for a reverse zone, expand the Reverse Lookup Zone folder.

    To create a resource record, do the following:

  4. In the left pane, right-click the zone and select the option that corresponds to the record type you want to create e.g., New Host (A).

  5. Fill in all required fields.

  6. Click OK.

    To delete a resource record, do the following:

  7. In the left pane, click on the zone the record is in.

  8. In the right pane, right-click on the record you want to delete and select Delete.

  9. Click Yes to confirm.

13.7.2.2 Using a command-line interface

To add a resource record, use the following command:

> dnscmd <DNSServerName> /recordadd <ZoneName> <NodeName> <RecordType> <RRData>

The following command adds an A record in the rallencorp.com zone:

> dnscmd dc1 /recordadd rallencorp.com wins01 A 19.25.52.2.25

To delete a resource record, use the following command:

> dnscmd <DNSServerName> /recorddelete <ZoneName> <NodeName> <RecordType> <RRData>

The following command deletes an A record in the rallencorp.com zone:

> dnscmd dc1 /recorddelete rallencorp.com wins01 A 19.25.52.2.25
13.7.2.3 Using VBScript
' This code shows how to add an A record and PTR record using ' the DNS WMI Provider ' ------ SCRIPT CONFIGURATION ------ strForwardRRAdd = "test-xp.rallencorp.com. IN A 192.32.64.13" strReverseRRAdd = "13.64.32.192.in-addr.arpa IN PTR test-xp.rallencorp.com" strForwardDomain = "rallencorp.com" strReverseDomain = "192.in-addr.arpa." ' ------ END CONFIGURATION --------- set objDNS = GetObject("winMgmts:root\MicrosoftDNS") set objRR = objDNS.Get("MicrosoftDNS_ResourceRecord") set objDNSServer = objDNS.Get("MicrosoftDNS_Server.Name="".""") ' Create the A record strNull = objRR.CreateInstanceFromTextRepresentation( _                   objDNSServer.Name, _                   strForwardDomain, _                   strForwardRRAdd, _                   objOutParam)        set objRR2 = objDNS.Get(objOutParam) WScript.Echo "Created Record: " & objRR2.TextRepresentation ' Create the PTR record strNull = objRR.CreateInstanceFromTextRepresentation( _                   objDNSServer.Name, _                   strReverseDomain, _                   strReverseRRAdd, _                   objOutParam)        set objRR2 = objDNS.Get(objOutParam) WScript.Echo "Created Record: " & objRR2.TextRepresentation ' This code shows how to delete an A and PTR record for the record ' I created in the previous example. strHostName  = "test-xp.rallencorp.com." set objDNS = GetObject("winMgmts:root\MicrosoftDNS") set objDNSServer = objDNS.Get("MicrosoftDNS_Server.Name="".""") set objRRs = objDNS.ExecQuery(" select * " & _                           " from MicrosoftDNS_ResourceRecord " & _                           " where OwnerName = """ & strHostName & """" & _                           " Or RecordData = """ & strHostName & """") if objRRs.Count < 1 then    WScript.Echo "No matches found for " & strHostName else    for each objRR in objRRs       objRR.Delete_       WScript.Echo "Deleted " & objRR.TextRepresentation    next end if

13.7.3 Discussion

13.7.3.1 Using a graphical user interface

The DNS Management snap-in is good for creating a small number of records, but if you need to add or delete more than a couple of dozen, then I'd recommend writing a batch file around dnscmd or preferably, use the DNS WMI Provider.

13.7.3.2 Using a command-line interface

Adding A, CNAME, and PTR resource records is pretty straightforward as far as the data you must enter, but other record types, such as SRV, require quite a bit more data. The help pages for /recordadd and /recorddelete display the required information for each record type.

13.7.3.3 Using VBScript

In the first example, I created A and PTR records using the CreateInstanceFrom TextRepresentation method, which is a MicrosoftDNS_ResourceRecord method that allows you to create resource records by passing in the textual version of the record. This is the textual representation of the A record used in the example:

test-xp.rallencorp.com IN A 192.32.64.13

The first parameter to this method is the DNS server name, the second is the name of the domain to add the record to, the third is the resource record, and the last is an out parameter that returns a reference to the new resource record.

In the second example, I find all resource records that match a certain hostname and delete them. This is done by first using a WQL query to find all resource records where the OwnerName equals the target host name (this will match any A records) and where RecordData equals the target host name (this will match any PTR records). The Delete_ method is called on each matching record, removing them on the DNS server.

13.7.4 See Also

MSDN: MicrosoftDNS_ResourceRecord



Active Directory Cookbook
Active Directory Cookbook, 3rd Edition
ISBN: 0596521103
EAN: 2147483647
Year: 2006
Pages: 456

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