- Backup your current DHCP scope configuration by running the following command in a Command Prompt:
netsh dhcp server \\”Server name” scope “scope subnet” dump > c:\dhcp.txt
- Modify the .txt file to reflect your changes using Notepad++. Why? Because the file encoding would be incorrect and can return errors when running the “netsh exec” command in a later step.
IE: if you want to change your subnet mask from /24 to /25, change:
Dhcp Server \\servername add scope 192.168.0.0 255.255.0.0 "xxx" "xxx" to Dhcp Server \\servername add scope 192.168.0.0 255.255.128.0 "xxx" "xxx"
Before saving your file, in Notepad++, set the encoding to ANSI.
- Stop “DHCP Server” service.
- Navigate to
and rename both the “dhcp.pat” and “dhcp.mbd” files to .old
- Start “DHCP Server” service.
- In a Command Prompt, run the following command to apply your new settings:
netsh exec c:\dhcp.txt
New settings should now have been applied. Sometimes, it is not reflected immediately to the DHCP console, just wait a few minutes.