Creating reservation for active leases.

Note: In Windows Server 2008 R2, active leases can be converted to reservations by just doing a right click in the DHCP Server management console. 🙂


If anyone is interested…or needs this in the future:



1. Dump all leases:

Netsh dhcp server scope show client


2. import the output (after cutting the first descriptional lines) to an excel file as space delimited file, remove unnecessary infos (i.e. “-” from the MACs and the unnecessary columns), then export to a file so that only the following info is retained in the file:




3. add reservation for all clients: create a script which processes the lines  of the output file and executes:

Netsh dhcp server scope add reservedip IP MAC

(here the IP and the MAC should come from the outputfile)



Script to read from file and create reservation (without error checking):




Const TEST_FILE_PATH = “C:ip-mac.txt”

Dim objFileSystemObject

Dim objOurExistingFileStream

Dim strLine

Dim oShell

Dim myComm

Set objFileSystemObject = CreateObject(“Scripting.FileSystemObject”)


‘Open our file

Set objOurExistingFileStream = objFileSystemObject.OpenTextFile(TEST_FILE_PATH)


Set oShell = WScript.CreateObject (“”)


‘Read out the file-content

Do Until objOurExistingFileStream.AtEndOfStream


‘each line contains an Ip and a MAC

strLine = objOurExistingFileStream.ReadLine

‘Wscript.Echo strLine

      myComm = “%COMSPEC% /c Netsh dhcp server scope add reservedip ” + strLine +” >>c:DhcpReservation.log”

strLine myComm,,True



‘Close it


Set objOurExistingFileStream = Nothing

Set objFileSystemObject = Nothing

Set oShell = Nothing


and finally logs will be available at c:DhcpReservation.log for verification & validation.

NOTE: Thanks to Mr.Balint who has shared the Script with US.

-RamaSubbu SK

Comments (3)

  1. teamdhcp says:

    Hey Scott,

    Your wish has been granted 🙂 . You can convert active leases to reservations easily by doing a right click in Windows Server 2008 R2 Beta DHCP Server.


    Raunak Pandya

    DHCP Server Team

  2. Gman says:

    thanks, I had a type mismatch vbs error on the final strLine entry. I added ‘on error resume next’ at the beginning and all worked OK.

    If you wanted to put a reservation name and description in as well, how do you do this?

    thanks 🙂

  3. Scott says:

    Wish List Item:  It would be great if you could just right click on an active lease in the management tool and select "Convert to reservation"!