4.7.4. Restrictions at the share level

The first category of restrictions allows the administrator to configure which shares can be used anonymously:

Key: HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\
Value: NullSessionShares (REG_SZ)

This registry value is also set by a security option, starting with Windows XP:

Network access: Shares that can be accessed anonymously

On default Windows systems, this value contains the COMCFG and DFS$ shares.

The IPC$ share does not appear in this registry value. However, it is always possible to connect anonymously to it. Restrictions for the IPC$ share are implemented at the named pipes level, as described in the next section.