SynAttackProtect

HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Data type

Range

Default value

REG_DWORD

0 | 1

0

Description

Determines whether the SYN flooding attack protection feature of TCP/IP is enabled. SYN flooding attack protection is enabled when the value of this entry is 1 and the value of the TcpMaxConnectResponseRetransmissions entry is at least 2 (see note below).

The SYN flooding attack protection feature of TCP detects symptoms of denial-of-service attacks (also known as SYN flooding ), and it responds by reducing the time the server spends on connection requests that it cannot acknowledge.

Value

Meaning

0

SYN flooding attack protection is not enabled.

1

SYN flooding attack protection is enabled.

Note Image Note

This value is used only when the number of SYN-ACK retransmissions is likely to impair the server, that is, when the value of the TcpMaxConnectResponseRetransmissions entry is at least 2.

Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry.

Related Entries

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TcpMaxConnectResponseRetransmissions

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TCPMaxHalfOpen

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TCPMaxHalfOpenRetried

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TcpMaxPortsExhausted