Increasing the number of IP addresses in the DHCP scope

Increase the number of IP Adress in an existing DHCP scope without deleting the scope, this will save your time

Edit the file and save

After this, delete the scope and run the below command to create the scope from the txt file

C:>netsh exec c:\dhcp.txt

This will automatically create the DHCP scope with the new subnet mask

This way you can change other configuration details along with subnet mask change, like IP range and Excluderanges

Also Read: DHCP Superscope

This has been implemented in our environment many times without any issues, grayed out Scope properties can be edited through this way and there is no downtime required while implementing this step

Hope this will help you to overcome the issue on expanding DHCP IP range without deleting the DHCP scope

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Also Read: How to change the subnet mask of DHCP scope

8 thoughts on “Increasing the number of IP addresses in the DHCP scope

  1. Paul

    Hi,

    I’ve followed your instructions to the “T”. I’ve managed to create the dump file and have made the changes within. Now I’m stuck at:

    netsh exec c:\dhcp.txt

    I keep getting an error in the syntax. The following command was not found: (a little square with a dot after)

    I haven’t deleted the old scope yet as I feel its too harsh with the above error looming. I cant get the dhcp.txt to execute back to my DHCP.

    Any help on this is most welcome. Thank you

    Reply
  2. Alexander

    Thank you.

    Really great post.
    Saved me alot of time since we had alot of reserved IP:s.

    Reply
  3. Pingback: DHCP Subnet Change

  4. Mario

    Well what about all the leases that have been issued out already. By deleting the scope, you loose all these… Very sad microsoft wont let us just change the subnet mask in the properties window of the scope.

    Reply
    1. Karl

      The import brings them all back, so this is a good guide!

      Reply
  5. Karl

    Is there something similar I can do to get failover to show up on my dhcp scope?
    The option doesn’t show up. If I make a new scope through the UI, it does.
    I figured that some option I had set was the problem, so I exported my dhcp as the guide indicates, deleted all but the first few lines, inactivated it, and then checked, and the option is still not there. Here are my lines in case you see something that I don’t.

    Changed the current scope context to 192.168.0.0 scope.

    Dhcp Server \\STMDP2012-1.STMARKWELS.LOCAL add scope 192.168.0.0 255.255.252.0 “All” “”
    Dhcp Server \\STMDP2012-1.STMARKWELS.LOCAL Scope 192.168.0.0 set state 0
    Dhcp Server \\STMDP2012-1.STMARKWELS.LOCAL Scope 192.168.0.0 set delayoffer 0

    Dhcp Server \\STMDP2012-1.STMARKWELS.LOCAL Scope 192.168.0.0 Add iprange 192.168.0.40 192.168.3.252 BOTH
    Dhcp Server \\STMDP2012-1.STMARKWELS.LOCAL scope 192.168.0.0 set napstate Off

    when I run those, the failover option still doesn’t appear on that scope.
    If you can help I would sure appreciate it!

    Reply

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