How To Modify An Existing DHCP Scope and Subnet

After searching through a lot of tutorials and  how-to's I created a step-by-step tutorial of how to change a DHCP scope.  Probably because you are running out of IP's to had out from your DHCP server.  First here is a IP Subnet Calculator.

  1. CMD: netsh dhcp server \\”Server name” scope “scope subnet name” dump>c:\dhcp.txt
  2. Take a few screen shots of your DHCP server settings, including your Scope Options.
  3. Modify the txt file with the correct DHCP scope and Subnet Mask by replacing any incorrect entries. Save it.  MAKE sure to also update all the relevant network addresses, or else you will get an error on import! (Example: Going from a 255.0 subnet to say 252.0 - do a find a replace for all 255.0, and replace with 252.o)
  4. Go into Services and STOP both DHCP client and Server services.
  5. Navigate to C:\Windows\System32\DHCP and rename both the "dhcp.pat" and "dhcp.mbd" files to .old
  6. Restart both DHCP client and Server services.
  7. CMD: netsh exec c:\dhcp.txt
  8. Open the DHCP admin tool and verify the scope is correct.
  9. Restart both DHCP services again to verify functionality.
  10. Make sure any Scope Options you had are re-created or re-make them.
  11. Lastly: DO NOT forget to now go to ANY static IP addressed things (computers, printers, servers, switches, etc.) and change the subnet.

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