The Password complexity is a Local Policy setting named "Passwords must meet complexity requirements" under Computer Configuration/Windows Settings/Security Settings/Account Policies/Password Policy.
In a Server Core installation there is no graphical user interface to set this policy.
Instead use secedit to import and export the security settings from a Full Installation of Windows Server 2008.
- First export your security configuration using the following command:
secedit /export /cfg C:securityconfig.cfg
- Then open notepad.exe and edit the C:securityconfig.cfg file.
Under [System Access] you should find PAssword complexity = 1
Change the value to 0 and save the file.
- Then fire up the next command to import the configuration:
secedit /configure /db C:Windowssecurity ew.sdb /cfg C:securityconfig.cfg /areas SECURITYPOLICY