Microsoft Knowledge Base Article 887429 contains the following Introduction:
This article describes Server Message Block (SMB) signing. SMB signing is a security mechanism in the SMB protocol and is also known as security signatures. SMB signing is designed to help improve the security of the SMB protocol. SMB signing was first available in Microsoft Windows NT 4.0 Service Pack 3 (SP3) and Microsoft Windows 98.
The following SMB topics are described in this article:
- The default configuration of SMB signing.
- How to configure SMB signing in Microsoft Windows Server 2003, Microsoft Windows XP, Microsoft Windows 2000, Windows NT 4.0, and Windows 98.
- How to determine whether SMB signing is enabled in a Network Monitor trace.
- Example SMB signing scenarios.