For whatever reason, standard user accounts can add a workstation to your domains. I have yet to figure a good reason out for this one. Microsoft does limit this to 10 computers per user account by default. That is little comfort for IT Professionals who are trying to maintain security on their networks. Here are two ways to close this security hole.
Change the number of workstations the users can add to your network. In this case, change it to zero.
· Click Start.
· Type ADSIEdit.msc and press Enter.
· Right mouse click ADSI Edit and select Connect to..
· Click OK
· Expand Default naming context.
· Right mouse click the distinguished name of your network and select Properties.
· Click ms-DS-MachineAccountQuota
· Click Edit.
· Set the number to 0.
The other option is to remove Authenticate Users from the User Right to add workstations to the domain.
· On your Domain Controller, Click Start à Administrative Tools à Group Policy Management.
· Either create a new GPO and link it to the Domain Controllers OU, or edit the Default Domain Controller Policy
· Expand Computer Configuration à Policies à Windows Settings à Security Settings à Local Polices à User Rights.
· Double click Add workstations to domain.
· Add in a group of users whom you want to be able to add workstations to the domain.
· Remove Authenticated Users from the policy.
· Click OK.