This article was previously published under Q121853
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If a Windows NT 3.1 computer is sharing a printer that is redirected to aWindows NT 3.5 computer, downlevel clients (like MS-DOS or Windows forWorkgroups) print jobs get stuck in the Windows NT 3.1 print queue.
When a Windows NT 3.1 computer sends a downlevel print job, it sends thejob as a null session. Null sessions are those where the user credentialsare blank during the request to setup a session. Because the downlevelclient may not have an account or because of a conflicting account on thesecond print server, downlevel jobs are sent as a null sessions. Securityis up to the first computer in this scenario.
Windows NT version 3.1 supports null sessions by default. However, WindowsNT version 3.5 does not provide this support unless specifically configuredto do so. This change was made in order to provide a higher default levelof security.
This problem can be resolved by modifying the registry on the computerrunning Windows NT 3.5 to allow null sessions to the print share.
WARNING: Using Registry Editor incorrectly can cause serious, system-wideproblems that may require you to reinstall Windows NT to correct them.Microsoft cannot guarantee that any problems resulting from the use ofRegistry Editor can be solved. Use this tool at your own risk.
Start Registry Editor and locate the following Registry subkey in the HKEY_LOCAL_MACHINE subtree:
NOTE: values will already exist and should not be replaced. If the values are accidentally deleted, just click Cancel and try again.
Select the first blank line after the values that currently exist. (The lines above should not be highlighted.) Add the name of the print share on Windows NT 3.5 you want to accept null sessions. This needs to be done for each share individually.
Click OK and exit Registry Editor.
Either shut down and restart Windows NT or from a command prompt type: NET STOP SERVER. Then type: NET START SERVER.
For a Windows NT LPD server to support print jobs that are redirected to asecond Windows NT shared print queue through a UNC name, NullSessionSharesmust be used. The UNC name of the printer share must be added as a nullshare on the second Windows NT print server. For example, if \\Server1 isthe LPD server and it's port is redirected to \\Server2\Printer, the UNCname \\SERVER2\Printer must be added to NullSessionShares on \\Server2.
For additional information on using LPD, please see the following resource:
Windows NT Resource Kit 3.51 Volume 2, Networking Guide; Chapter 18,"Internetwork Printing with TCP/IP," page 357.
wfw wfwg prodnt print lpr lpd stuck null shares Unix local port UNC