Windows Server – Change a DHCP Scopes Subnet Mask
KB ID 0001177 Problem You have probably tried to do this and found he option ‘greyed out’ because in the DHCP management console you can’t change the subnet mask of a scope. I needed to change a clients DHCP scope because I was changing their subnet from /24 to /16. I could have simply deleted and recreated the scope, but they has a lot of custom settings for their phone system, and hundreds of reservations (which...