Null Session Share not working on Windows 7

Question

I have a computer running Windows 7 SP 1 Ultimate (IP 192.168.11.100). I need to create a Null Session Share (named WIA_RIS_SHARE) for Serva PXE Server to be able to install Windows XP via networking.

According to its docs, I have created:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters\NullSessionShares = "WIA_RIS_SHARE"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\LSA\restrictanonymous = 0

I have done it at a Windows XP SP3 (IP 192.168.11.2), and it seems to work OK.

This is how I check it (from another computer on the same LAN):

C:\>net view \\192.168.11.2
Shared resources at \\192.168.11.2
Resource name           Type    Used ad Comments
-----------------------------------------------------------------------------
WIA_RIS_SHARE       Disk

But when checking it on the Win7 machine:

C:\>net view \\192.168.11.100
System error 5.
Access denied.

As far as I know, it is supposed that a Null Share Session should allow browsing (enumeration) of shared resources, so I believe this is a appropriate test.

What else could I need to do to enable Null Session Shares on Windows 7?

Answer 1

I think you didn't read Serva's NSS documentation correctly; please click on the "WINDOWS 7" chapter.

For Windows 7 hosted NSSs when clients are RIS these are the shown steps:

1. Enabling Anonymous Logon:

   1. Run the Control Panel

   2. Navigate to:

   Network and Internet\Network and Sharing Center\Change advanced sharing settings\

   Select:

   Turn off password protected sharing

   3. Save changes and close the Control Panel.

2. Creating the Share:

    1. From File Explorer right click the TFTP root directory and select "Properties."

    2. Select the "Sharing" tab and click [Advanced Sharing...]

    3. Check "Share this folder", set "Share Name" = WIA_RIS_SHARE and click [Permissions]

    4. Remove all users/groups then add the user "Guest" with "Read" rights only and 
       click [OK] twice.

    5. Back at the Properties dialog now select the "Security" tab and click [Edit...]

    6. Click [Add..], enter the user "Guest" and click [OK]

    7. Selecting the user "Guest" at the "Group or user names:" pane edit its permissions 
       at the "Permissions for Guest" pane. Make sure you check the "Allow" column with 
       "Read & execute", "List folder contents" and, "Read" permissions, then click 
       [OK] twice.

Just in the case you need to create an NSS for clients (other than RIS) that mandatorily require older dialects like “LANMAN1.0”, “LANMAN1.2”, etc, then you might need extra steps in order to enable those dialects at your host; i.e.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters\NullSessionShares = "WIA_RIS_SHARE"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\LSA\restrictanonymous = 0

In your case these extra steps are not necessary as you are booting RIS clients...