Article ID: 124184 - View products that this article applies to.
This article was previously published under Q124184
When an application is started using the system account, it logs on with null credentials. If it attempts to access a remote Windows NT 3.5 server resource (using a null session), it fails. Scheduler service scripts (AT command) and other service or application operations attempting to access server resources over the network receive errors such as the following:
When an application using the system account uses a UNC name to access a shared resource, the following error message is returned:
Error 5: Access is denied.
NOTE: Scheduler service script error messages can be caught by redirecting the AT command to a file.
File Not Found
Services, including the Scheduler, use null session support when logged on as system account to interact with desktop.
Windows NT version 3.1 supports null sessions by default. However, Windows NT version 3.5 does not provide this support unless specifically configured to do so. This change was made in order to provide a higher default level of security.
When a process is running under the context of the system account, it attempts to use a null session for credentials to acquire a resource access. AT scripts performing commands, such as NET USE, will default to these credentials. A protocol analyzer trace reveals the null session request associated with the Server Message Block (SMB) Session Setup & X in which no explicit credentials are passed.
Do not use the system account. Services, such as Scheduler, and custom applications can be configured using user-specific accounts. User-specific accounts provide user level security based on a specific account and associated password.
NOTE: For more information, see Chapter 15: Server Manager, Assigning a Logon Account to the Schedule Service in the "Windows NT Server 3.5 System Guide."
If you desire null session support, you can modify the registry of each remote resource computer as follows.
TITLE : Local System Account and Null Sessions in Windows NT
TITLE : Using the System Account as a Service in Windows NT 3.5
TITLE : LMHOSTS #Include Directives Requires Null Session Support
Article ID: 124184 - Last Review: November 1, 2006 - Revision: 2.1
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