IPv6 TCP data retransmissions will be configured to prevent resources from becoming exhausted.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-21956	3.156	SV-32450r1_rule	ECSC-1	Low

Description
This check verifies Windows is configured to control the maximum number of times that IPv6 TCP retransmits unacknowledged data segments before aborting the attempt to prevent resources from becoming exhausted.

STIG	Date
Windows Server 2008 R2 Domain Controller Security Technical Implementation Guide	2015-06-16

Details

Check Text ( C-32916r1_chk )
Analyze the system using the Security Configuration and Analysis snap-in. Expand the Security Configuration and Analysis tree view. Navigate to Local Policies -> Security Options. If the value for “MSS: (TcpMaxDataRetransmissions IPv6) How many times unacknowledged data is retransmitted (3 recommended, 5 is the default)” is not set to “3” or less, then this is a finding. The policy referenced configures the following registry value: Registry Hive: HKEY_LOCAL_MACHINE Subkey: \System\CurrentControlSet\Services\Tcpip6\Parameters\ Value Name: TcpMaxDataRetransmissions Type: REG_DWORD Value: 3 (or less)

Check Text ( C-32916r1_chk )

Analyze the system using the Security Configuration and Analysis snap-in.
Expand the Security Configuration and Analysis tree view.
Navigate to Local Policies -> Security Options.

If the value for “MSS: (TcpMaxDataRetransmissions IPv6) How many times unacknowledged data is retransmitted (3 recommended, 5 is the default)” is not set to “3” or less, then this is a finding.

The policy referenced configures the following registry value:

Registry Hive: HKEY_LOCAL_MACHINE
Subkey: \System\CurrentControlSet\Services\Tcpip6\Parameters\

Value Name: TcpMaxDataRetransmissions

Type: REG_DWORD
Value: 3 (or less)

Fix Text (F-28860r1_fix)
Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> “MSS: (TcpMaxDataRetransmissions IPv6) How many times unacknowledged data is retransmitted (3 recommended, 5 is the default)” to “3” or less.