REG: TCP/IP Transport Entries, PART 2

• Windows NT operating system version 3.1
• Windows NT Advanced Server version 3.1

• FTP Server Service Entries for TCP/IP
• NBT Parameters for TCP/IP
• Streams Parameters for TCP/IP
• Windows Sockets Entries for TCP/IP

This is the second of two articles on these entries; for the other entries, see "TCP/IP Transport Entries, Part 1."

TCP/IP TRANSPORT ENTRIES

The various TCP/IP keys do not appear in the Registry unless TCP/IP is installed using the Network icon in Control Panel. With Registry Editor, you can modify the following parameters for the TCP/IP transport. This section does not include all the TCP/IP parameters that can be set using the Networks application in Control Panel.

The startup parameters defined in this section are found in these subkeys of HKEY_LOCAL_MACHINE\SYSTEM\System\CurrentControlSet\Services:

   TCPIP\Parameters
   Adapter_name#\Parameters\TCPIP, (where adapter_name# indicates a
                           Services subkey for a network adapter
                           card)
   Ftpsvc\Parameters
   NBT\Parameters
   Streams\Parameters

FTP SERVER SERVICE ENTRIES FOR TCP/IP

The following Registry path contains parameters that affect the behavior of the FTP server service component:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Ftpsvc\Parameters

There can also be an AccessCheck subkey under Ftpsvc, which allows access to FTP for new users. If the AccessCheck subkey exists, but cannot be opened, the user is refused FTP services. If the subkey exists but can only be opened for read access, the user is granted read-only FTP access. If the subkey does not exist, it is not used to influence FTP access. By default, this subkey does not exist and therefore has no impact on FTP operations. An administrator can create this Registry subkey and attach specific access controls. which will serve to control user access to the FTP service.

AllowAnonymous   REG_DWORD   0 or 1

Controls anonymous logins. Anonymous logins are only allowed if this value is non-zero (true).

AnnotateDirectories   REG_DWORD   0 or 1

When this value is 1, every time a user changes directories (that is, sends the server a CWD command), an attempt is made to open a file named ~FTPSVC~.CKM in the new directory. If this file is found, its contents are sent to the user as part of the successful reply to the CWD command. This may be used to attach annotations to specific directories. This value is used as a default for new users. Users can toggle their own personal annotate directories flag with the site-specific CKM command (SITE CKM).

AnonymousOnly   REG_DWORD   0 or 1

When this value is 1, only anonymous logins are allowed. Otherwise, non- anonymous logins are allowed as well.

AnonymousUserName   REG_SZ   UserName

Contains the anonymous login alias. When a user attempts an anonymous login, the username specified ("anonymous") is mapped to this Registry value for authentication and impersonation. The password for this account is stored in an LSA secret object named FTPD_ANONYMOUS_DATA.

ConnectionTimeout   REG_DWORD   Seconds

Specifies the time to allow clients to remain idle before forcibly disconnecting them. This prevents idle clients from consuming server resources indefinitely. This value may be set to 0 if time-outs are not to be enforced. If set to 0, idle clients may remain connected indefinitely.

DebugFlags   REG_DWORD   BitFields

Used only by the debugging (checked) builds of the FTP Server to control the output of various debugging information. This value is unused (and ignored) by retail builds.

ExitMessage   REG_SZ   Message

Specifies a signoff message sent to an FTP client upon receipt of a QUIT command.

GreetingMessage   REG_MULTI_SZ   Strings

Specifies the message (if this value exists in the Registry) to be sent to new clients after their account has been validated. In accordance with de facto Internet behaviour, if a client logs on as anonymous and specifies an identity starting with a '-' (minus), then this greeting message is not sent.

HomeDirectory   REG_EXPAND_SZ   Path

Specifies the initial home directory for new clients. After a new client is validated, an attempt is made to change to this directory with the Chdir command. If this directory is inaccessible, the client is refused FTP services. If Chdir is successful, then an attempt is made to change to a directory with the same name as the client’s username. If this fails, an attempt is made to change to a directory called DEFAULT. If this fails, the current directory is left at home. If a new client connects and finds the home directory is inaccessible, an event is written to the event log.

LogAnonymous   REG_DWORD   0 or 1

When this value is 1, all successful anonymous logins are logged to the system event log.

LogNonAnonymous   REG_DWORD   0 or 1

When this value is 1, all successful non-anonymous logins are logged to the system event log.

MaxClientsMessage   REG_SZ   Message

Specifies the message (if this value exists in the Registry) to be sent to a client if the maximum number of clients has been reached or exceeded. This indicates that the server is currently servicing the maximum number of simultaneous clients and is refusing additional clients. See MaxConnections.

MaxConnections   REG_DWORD   0 or 1

Specifies the maximum number of simultaneous clients the server will service. This value may be set to 0 if there is to be no limit on simultaneous clients.

MsdosDirOutput   REG_DWORD   0 or 1

When this value is 1, the output of the LIST command (usually sent as a result of a DIR command from the client) will look like the output of the MS-DOS dir command. If this value is 0, the output of the LIST command looks like the output of the Unix ls command.

This value also controls slash flipping in the path sent by the PWD command. When this value is 1 (true), the path contains backward slashes (\). If this value is 0 (false), the path contains forward slashes (/). This value is used as a default for new users. Users can toggle their own personal MS-DOS directory output flag with the site-specific DIRSTYLE command (SITE DIRSTYLE).

ReadAccessMask   REG_DWORD   BitFields

This value is a bitmask and controls the read ability of the various disk volumes in the system. Drive A corresponds to bit 0, drive B corresponds to bit 1, drive C corresponds to bit 2, and so on. A user may only read from a specific volume if the corresponding bit is set.

WriteAccessMask   REG_DWORD   BitFields

This value is a bitmask and controls the write ability of the various disk volumes in the system. Drive A corresponds to bit 0, drive B corresponds to bit 1, drive C corresponds to bit 2, and so on. A user may only write to a specific volume if the corresponding bit is set.

NBT PARAMETERS FOR TCP/IP

NBT is the NetBIOS over TCP/IP service. Parameters for TCP/IP are also configured under NBT in the following Registry path:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NBT\Parameters

MaxPreload   REG_DWORD   Number

Specifies the maximum NBT number of entries for LMHOSTS that are preloaded into the NBT NetBIOS name cache. LMHOSTS is a file located in the directory specified by DatabasePath.

NbProvider   REG_SZ   DLL name

This value is only present for network services that provide a NetBIOS interface. Its presence causes LanMan information to be maintained for the transport. The value data represents the RPC provider string used to select the proper DLL for interfacing RPC to the transport.

NbtKeepAlive   REG_DWORD   Number in seconds

Specifies how often NBT will generate keep-alive traffic. When NBT determines that no activity has occurred on a connection for the specified time interval, it will generate keep-alive traffic to probe the connection. If TCP/IP is unable to deliver this traffic, it marks the connection as down and notifies NBT.

PermanentName   REG_SZ   Unique name

Specifies the permanent name of the NetBIOS node for NBT. In many NetBIOS implementations, this is the MAC address. This name must be unique.

STREAMS PARAMETERS FOR TCP/IP

The TCP/IP parameter for Streams are found under the following Registry path:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Streams\Parameters

MaxMemoryUsage   REG_DWORD   Number of bytes

Specifies the maximum amount of memory that can be allocated to the Streams environment. Once this limit is reached, Streams will fail allocation requests made by Streams-based drivers.

WINDOWS SOCKETS ENTRIES FOR TCP/IP

All Windows Sockets parameters can be set by choosing the Network icon in Control Panel. These parameters are found in two locations, as shown here.

HKEY_LOCAL_MACHINE\SYSTEM\

CurrentControlSet\Services\Winsock\Parameters

Transports   REG_Multi_SZ   Strings

Contains the Regisry key names of installed transports that support Windows Sockets. If TCP/IP is the only installed transport that supports Windows Sockets, then this value is Tcpip. The Windows Sockets DLL uses the strings in Transports to find information about each transport.

HKEY_LOCAL_MACHINE\SYSTEM\

CurrentControlSet\Services\TCPIP\Parameters\Winsock

HelperDllName   REG_EXPAND_SZ   Path and filename

Specifies the name of the Windows Sockets helper DLL for the TCP/IP transport. This value is set by the Windows Sockets DLL and is not a user settable parameter.

IRPStackSize   REG_DWORD   Number

Specifies the number of IRP stack locations needed by AFD, the driver used for Windows Sockets. The default is sufficient for all existing transports, but new transports may be developed that need more IRP stack locations.

Mapping   REG_BINARY

Identifies the address families, socket types, and protocols supported by the transport. This value is set by the Windows Sockets DLL and is not a user settable parameter.

MaxSockAddrLen   REG_DWORD   Octets

Specifies the maximum length of socket addresses for the INET sockets family. This value is set by the Windows Sockets DLL and is not a user settable parameter.

MinSockAddrLen   REG_DWORD   Octets

Specifies the minimum length of socket addresses for the INET sockets family. This value is set by the Windows Sockets DLL and is not a user settable parameter.

Reference: "The Windows NT Resource Kit for Operating System Version 3.1."