On a Windows DHCP Server, if you have a lot of DHCP reservations in a particular scope on a server, and you have the need to migrate them to another scope (on the same or another server), you can do so quickly through netsh (a "legacy" command-line tool to perform network configuration on a Windows system).
Fire up a command prompt (or Powershell). First dump, the current scope configuration to a text file:
netsh dhcp server <serverIPAddress> scope <scopeAddress> dump > dump.txt
Note that if you run the command on the server where the originating scope is located, you don't need to specify the IP address/hostname of the server.
Sometimes it may become necessary to make changes to a DHCP scope on your Windows DHCP Server. Unfortunately, for existing scopes, not all scope options are editable, and it can become quite a hassle to recreate the scope, especially when there are a lot of reservations. Luckily, there's a workaround which allows you to edit the scope options, which is by using netsh.
It is not possible for netsh to directly edit scope options, but you can create a dump of the complete scope configuration (including all reservations), edit the resulting file, and import it back into the DHCP server. For this to work, you'll need admin (elevated) privileges on the DHCP server.
For proper troubleshooting of DHCP traffic, it may sometimes be necessary to capture live data on your network. There are a lot of ways on how this is accomplished, so I won't go into too much detail on all the methods available, nor will I explain what DHCP does or how it works.
DHCP (Dynamic Host Configuration Protocol) is used for automatic configuration of a host's network settings, such as IP address, gateway, routing, and more. It works by sending broadcasts using IP/UDP on ports 67 (servers) and 68 (clients). For more information on DHCP, read the explanation on Wikipedia.
In order to capture DHCP traffic, we would then have to monitor packets specifically on port 67/udp and 68/udp. ...
Upon unauthorizing a Windows DHCP server, you may get the following error:
The parameter is incorrect.
Most commonly, there are two reasons for this error to occur.
If you have just unauthorized a DHCP server, it may take a while for AD to replicate the change to other domain controllers. As a result, the DHCP server may still think it's authorized, whereas it is not. Either wait for, or trigger AD replication throughout your network.
Another reason for this error to occur is the presence of another DHCP server in AD that no longer exists. You can check this with the netsh dhcp command, available on any server with the DHCP server role installed: