windows-itpro-docs/windows/keep-secure/network-security-minimum-session-security-for-ntlm-ssp-based-including-secure-rpc-clients.md

title, description, ms.assetid, ms.pagetype, ms.prod, ms.mktglfcycl, ms.sitesec, author

title	description	ms.assetid	ms.pagetype	ms.prod	ms.mktglfcycl	ms.sitesec	author
Network security Minimum session security for NTLM SSP based (including secure RPC) clients (Windows 10)	Describes the best practices, location, values, policy management and security considerations for the Network security Minimum session security for NTLM SSP based (including secure RPC) clients security policy setting.	89903de8-23d0-4e0f-9bef-c00cb7aebf00	security	W10	deploy	library	brianlic-msft

Network security: Minimum session security for NTLM SSP based (including secure RPC) clients

Applies to

• Windows 10 Describes the best practices, location, values, policy management and security considerations for the Network security: Minimum session security for NTLM SSP based (including secure RPC) clients security policy setting.

Reference

This policy setting allows a client device to require the negotiation of 128-bit encryption or NTLMv2 session security. These values are dependent on the Network security: LAN Manager Authentication Level policy setting value.

Possible values

• Require NTLMv2 session security The connection fails if strong encryption (128-bit) is not negotiated.
• Require 128-bit encryption The connection fails if the NTLMv2 protocol is not negotiated.

Best practices

Practices in setting this policy are dependent on your security requirements.

Location

Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options

Default values

The following table lists the actual and effective default values for this policy. Default values are also listed on the policy’s property page.

Server type or GPO	Default value
Default Domain Policy	Not defined
Default Domain Controller Policy	Not defined
Stand-Alone Server Default Settings	Require 128-bit encryption
DC Effective Default Settings	Require 128-bit encryption
Member Server Effective Default Settings	Require 128-bit encryption
Client Computer Effective Default Settings	Require 128-bit encryption

  ## Policy management This section describes features and tools that are available to help you manage this policy. ### Restart requirement None. Changes to this policy become effective without a device restart when they are saved locally or distributed through Group Policy. ### Policy conflicts The settings for this security policy are dependent on the **Network security: LAN Manager Authentication Level policy** setting value. For info about this policy, see [Network security: LAN Manager authentication level](network-security-lan-manager-authentication-level.md). ## Security considerations This section describes how an attacker might exploit a feature or its configuration, how to implement the countermeasure, and the possible negative consequences of countermeasure implementation. ### Vulnerability Network traffic that uses the NTLM Security Support Provider (NTLM SSP) could be exposed such that an attacker who has gained access to the network can create man-in-the-middle attacks. ### Countermeasure Enable all options that are available for the **Network security: Minimum session security for NTLM SSP based (including secure RPC) clients policy** setting. ### Potential impact Client devices that enforce these settings cannot communicate with older servers that do not support them. ## Related topics [Security Options](security-options.md)