NetBIOS configuration Parameters on TCP

All NetBT parameters are registry values that are one of the two different subkeys that are located in HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services:

Netbt\parameters

Netbt\adapters\interfaces\interface, where interface refers to the subkeys of the network interface that NetBT binds. The following items are unique to each interface. If the system is configured with DHCP, using the ipconfig/renew command at the command prompt will take effect on the parameter changes. Otherwise, you must reboot the system so that the changes to these parameters take effect.

Parameters that can be configured using Registry Editor

During the TCP/IP component installation process, NCPA installs the default values for the following parameters. You can modify them using Registry Editor (Regedt32.exe). Some of the parameters in the registry are visible by default, but most of the parameters must be created to modify the default values for NetBT driver settings.

Backlogincrement

Item: Netbt\parameters

Numeric Type: REG_DWORD-Digital

Valid range: 3-0x14 (decimal 1-20)

Default value: 3

Description: This parameter is added to solve the Internet SYN attack problem. When a NetBIOS TCP port (139) is connected, the system creates a backlogincrement if the number of free connection blocks is less than 2

A new connection block. Each connection block consumes 78 bytes of memory. You can use the Maxconnbacklog parameter to set limits on the total number of connections allowed. A connection block is required for each NetBT connection.

BcastNameQueryCount

Item: Netbt\parameters

Numeric Type: REG_DWORD-Digital

Valid range: 1-0XFFFF

Default value: 3

Description: This value determines the number of times NetBT broadcasts a specific name query without receiving a response.

Bcastquerytimeout

Item: Netbt\parameters

Numeric Type: REG_DWORD-time (MS)

Valid range: 100-0XFFFFFFFF

Default value: 0x2ee (decimal 750)

Description: This value determines the time interval between two consecutive broadcast name queries of the same name.

BroadcastAddress

Item: Netbt\parameters

Numeric type: reg_dword-4 byte, small-ended encoded IP address

Valid range: 0-0XFFFFFFFF

Default value: Broadcast address for each network full "1"

Note: For all packets associated with the broadcast name, this parameter forces NetBT to use the specified address. By default, NetBT uses a corresponding full "1" broadcast address for each network (that is, for a network with an address of 10.101.0.0, a subnet mask of 255.255.0.0, and a subnet broadcast address of 10.101.255.255). For example, this parameter is set if the network uses a broadcast address of full "0" (using the usezerobroadcast TCP/IP parameter setting). In the example above, the appropriate subnet broadcast address is 10.101.0.0. The parameter is then set to 0x0b650000. This parameter is global and is used for all subnets that NetBT binds.