Windows NT Print Browsing Architecture

• Microsoft Windows NT Workstation versions 3.51 and 4.0
• Microsoft Windows NT Server versions 3.51 and 4.0

SUMMARY

Windows NT leverages the familiar browsing mechanism found in File Manager to enumerate printers for remote printing. This article describes the mechanism used for print browsing in a Windows NT Environment and the registry keys that effect its behavior.

MORE INFORMATION

How Shared Printers Are Found

When a user chooses to browse for a printer in the domain, a remote procedure call (RPC) (EnumPrinters) is made to the browse master. EnumPrinters returns only the computers in the browse list that have set the printer flag (SV_TYPE_PRINT) in their host announcements.

For additional information on how the master browser is elected, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q102878
   TITLE     : Information on Browser Operation

Client Request

FRAME: Base frame properties ETHERNET: 802.3 Length = 1042 LLC: UI DSAP=0xE0 SSAP=0xE0 C IPX: NetBIOS Packet - 6112.08003E3046DE.455 -> 6112.02608C3F3E55.455 - 0 Hops NBIPX: Session Data SMB: C transact TransactNmPipe, FID = 0x80a MSRPC: c/o RPC Request: call 0x1 opnum 0x0 context 0x0 hint 0x364 R_WINSPOOL: RPC Client call winspool:RpcEnumPrinters(..) R_WINSPOOL: DWORD Flags = 64 (0x40) R_WINSPOOL: STRING_HANDLE Name = \\NTSERVER R_WINSPOOL: DWORD Level = 1 (0x1) R_WINSPOOL: LPBYTE pPrinterEnum [..] = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00... R_WINSPOOL: DWORD cbBuf = 804 (0x324)

Server Response

FRAME: Base frame properties ETHERNET: 802.3 Length = 970LLC: UI DSAP=0xE0 SSAP=0xE0 CIPX: NetBIOS Packet - 6112.02608C3F3E55.455 -> 6112.08003E3046DE.455 - 0 Hops NBIPX: Session Data SMB: R transact TransactNmPipe (response to frame 89) MSRPC: c/o RPC Response: call 0x1 context 0x0 hint 0x338 cancels 0x0 R_WINSPOOL: RPC Server response winspool:RpcEnumPrinters(..) R_WINSPOOL: LPBYTE pPrinterEnum [..] = 08 00 00 00 DA 02 00 00 B4 02 00 00 B2 02 00 00 08 00 00 00 58 02 00... R_WINSPOOL: LPDWORD pcbNeeded = 460 (0x1CC) R_WINSPOOL: LPDWORD pcReturned = 3 (0x3) R_WINSPOOL: Return Value = 0 (0x0)

The network trace above shows the network client receiving back a response from the server containing information from the RPC call EnumPrinters. (Additional information on this function is available in the Win32 SDK.)

How Do Existing Printers Get Enumerated to the Print Browse Master

Windows NT Server and Workstation computers update the browse master by default every 10 minutes with print share information. This is done via the Win32 API AddPrinter.

Below is a network trace fragment that demonstrates a client enumerating shared resources to the print browse master:

FRAME: Base frame propertiesETHERNET: 802.3 Length = 458LLC: UI DSAP=0xE0 SSAP=0xE0 CIPX: NetBIOS Packet - 6112.08003E3046DE.455 -> 6112.02608C3F3E55.455 - 0 Hops NBIPX: Session Data SMB: C transact TransactNmPipe, FID = 0x200c MSRPC: c/o RPC Request: call 0x1 opnum 0x5 context 0x0 hint 0x11C R_WINSPOOL: RPC Client call winspool:RpcAddPrinter(..) R_WINSPOOL: STRING_HANDLE pName = \\NTSERVER R_WINSPOOL: PPRINTER_CONTAINER pPrinterContainer {..} R_WINSPOOL: DWORD Level = 1 (0x1) R_WINSPOOL: (Untyped 1) PrinterInfo {..} R_WINSPOOL: Switch Value = 1 (0x1) R_WINSPOOL: LPPRINTER_INFO_1W pPrinterInfo1 {..} R_WINSPOOL: DWORD Flags = 24 (0x18) R_WINSPOOL: LPWSTR pDescription = 35780264 (0x221F6A8) R_WINSPOOL: LPWSTR pName = 35781864 (0x221FCE8) R_WINSPOOL: LPWSTR pComment = 12163832 (0xB99AF8) R_WINSPOOL: LPWSTR pDescription = \\NTCLIENT\Lexmark Optra PS,Lexmark Optra PS, R_WINSPOOL: LPWSTR pName = \\NTCLIENT\Lexmark Optra PS R_WINSPOOL: LPWSTR pComment = R_WINSPOOL: PDEVMODE_CONTAINER pDevModeContainer {..} R_WINSPOOL: DWORD cbBuf = 0 (0x0) R_WINSPOOL: LPBYTE pDevMode = 0 (0x0) R_WINSPOOL: PSECURITY_CONTAINER pSecurityContainer {..} R_WINSPOOL: DWORD cbBuf = 0 (0x0) R_WINSPOOL: LPBYTE pSecurity = 0 (0x0)

Registry Entries

Below is a list of registry entries that will manipulate client and server behavior in regard to print browsing.

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print

   DisableServerThread     REG_DWORD

   Range: 0 or 1

   Default: 0 (false)

   Set this to 1 (true) to disable the browse thread on the current
   computer. This thread is used to call other print servers to notify them
   that this printer exists.

   ServerThreadTimeout     REG_DWORD

   Range: Milliseconds

   Default:  36,000 (36 seconds)

   Specifies the amount of time the ServerThread sleeps for before it calls
   all the other print servers to notify them of the printers on this
   computer.

   NetPrinterDecayPeriod     REG_DWORD

   Range: Milliseconds

   Default:  3,600,000 (1 hour)

   Specifies how long to cache a network printer. The cache is used to
   present the list of printers when the browse dialog is used.

   RefreshTimesPerDecayPeriod     REG_DWORD

   Range: 1 - 5

   Default:  2

   Specifies how many times to inform the browse masters and backup servers
   per decay period. Default value is two times per hour. Do not set a zero
   value if you specify both RefreshTimesPerDecayPeriod and
   ServerThreadTimeout; the system will wait for the maximum of either the
   ServerThreadTimeout or the RefreshTimesPerDecayPeriod.

Non-Printing Registry Changes

   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer
   \Parameters

   NOTE: The above registry key is one path; it has been wrapped for
   readability.

   SizReqBuf     REG_DWORD

   Range: 512 - 65536 bytes

   Default: 4356

   Specifies the size of request buffers that the server uses. Small
   buffers use less memory; large buffers may improve performance. For an
   optional value try 4410.(Hex)

Keywords          : ntprint NTSrvWkst kbnetwork
Version           : WinNT:3.51,4.0
Platform          : winnt