NetServerEnum
returns, dependant on the bit mask specified, servers and/or machines that are visible on the local domain, bit masks can be combined using
Or to produce a customized listing more suitable to specific needs. No special group membership is required to successfully execute the
NetServerEnum function.
NetServerEnum, depending on the data level passed, returns only
minimal information about each connected machine. Extended information for specific servers can be obtained using the WNetEnumResource
function instead.
The illustration shows the two machines on my local network,
imaginatively named.
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Option Explicit
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved.
' Some pages may also contain other copyrights by the author.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Distribution: You can freely use this code in your own
' applications, but you may not reproduce
' or publish this code on any web site,
' online service, or distribute as source
' on any media without express permission.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'Windows type used to call the Net API
Private Const MAX_PREFERRED_LENGTH As Long = -1
Private Const NERR_SUCCESS As Long = 0&
Private Const ERROR_MORE_DATA As Long = 234&
Private Const SV_TYPE_WORKSTATION As Long = &H1
Private Const SV_TYPE_SERVER As Long = &H2
Private Const SV_TYPE_SQLSERVER As Long = &H4
Private Const SV_TYPE_DOMAIN_CTRL As Long = &H8
Private Const SV_TYPE_DOMAIN_BAKCTRL As Long = &H10
Private Const SV_TYPE_TIME_SOURCE As Long = &H20
Private Const SV_TYPE_AFP As Long = &H40
Private Const SV_TYPE_NOVELL As Long = &H80
Private Const SV_TYPE_DOMAIN_MEMBER As Long = &H100
Private Const SV_TYPE_PRINTQ_SERVER As Long = &H200
Private Const SV_TYPE_DIALIN_SERVER As Long = &H400
Private Const SV_TYPE_XENIX_SERVER As Long = &H800
Private Const SV_TYPE_SERVER_UNIX As Long = SV_TYPE_XENIX_SERVER
Private Const SV_TYPE_NT As Long = &H1000
Private Const SV_TYPE_WFW As Long = &H2000
Private Const SV_TYPE_SERVER_MFPN As Long = &H4000
Private Const SV_TYPE_SERVER_NT As Long = &H8000
Private Const SV_TYPE_POTENTIAL_BROWSER As Long = &H10000
Private Const SV_TYPE_BACKUP_BROWSER As Long = &H20000
Private Const SV_TYPE_MASTER_BROWSER As Long = &H40000
Private Const SV_TYPE_DOMAIN_MASTER As Long = &H80000
Private Const SV_TYPE_SERVER_OSF As Long = &H100000
Private Const SV_TYPE_SERVER_VMS As Long = &H200000
Private Const SV_TYPE_WINDOWS As Long = &H400000 'Windows95 and above
Private Const SV_TYPE_DFS As Long = &H800000 'Root of a DFS tree
Private Const SV_TYPE_CLUSTER_NT As Long = &H1000000 'NT Cluster
Private Const SV_TYPE_TERMINALSERVER As Long = &H2000000 'Terminal Server
Private Const SV_TYPE_DCE As Long = &H10000000'IBM DSS
Private Const SV_TYPE_ALTERNATE_XPORT As Long = &H20000000'rtn alternate transport
Private Const SV_TYPE_LOCAL_LIST_ONLY As Long = &H40000000'rtn local only
Private Const SV_TYPE_DOMAIN_ENUM As Long = &H80000000
Private Const SV_TYPE_ALL As Long = &HFFFFFFFF
Private Const SV_PLATFORM_ID_OS2 As Long = 400
Private Const SV_PLATFORM_ID_NT As Long = 500
'Mask applied to svX_version_major in
'order to obtain the major version number.
Private Const MAJOR_VERSION_MASK As Long = &HF
Private Type SERVER_INFO_100
sv100_platform_id As Long
sv100_name As Long
End Type
Private Declare Function NetServerEnum Lib "netapi32" _
(ByVal servername As Long, _
ByVal level As Long, _
buf As Any, _
ByVal prefmaxlen As Long, _
entriesread As Long, _
totalentries As Long, _
ByVal servertype As Long, _
ByVal domain As Long, _
resume_handle As Long) As Long
Private Declare Function NetApiBufferFree Lib "netapi32" _
(ByVal Buffer As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" _
Alias "RtlMoveMemory" _
(pTo As Any, uFrom As Any, _
ByVal lSize As Long)
Private Declare Function lstrlenW Lib "kernel32" _
(ByVal lpString As Long) As Long
Private Sub Form_Load()
Command1.Caption = "Net Server Enum"
End Sub
Private Sub Command1_Click()
Call GetServers(vbNullString)
End Sub
Private Function GetServers(sDomain As String) As Long
'lists all servers of the specified type
'that are visible in a domain.
Dim bufptr As Long
Dim dwEntriesread As Long
Dim dwTotalentries As Long
Dim dwResumehandle As Long
Dim se100 As SERVER_INFO_100
Dim success As Long
Dim nStructSize As Long
Dim cnt As Long
nStructSize = LenB(se100)
'Call passing MAX_PREFERRED_LENGTH to have the
'API allocate required memory for the return values.
'
'The call is enumerating all machines on the
'network (SV_TYPE_ALL); however, by Or'ing
'specific bit masks for defined types you can
'customize the returned data. For example, a
'value of 0x00000003 combines the bit masks for
'SV_TYPE_WORKSTATION (0x00000001) and
'SV_TYPE_SERVER (0x00000002).
'
'dwServerName must be Null. The level parameter
'(100 here) specifies the data structure being
'used (in this case a SERVER_INFO_100 structure).
'
'The domain member is passed as Null, indicating
'machines on the primary domain are to be retrieved.
'If you decide to use this member, pass
'StrPtr("domain name"), not the string itself.
success = NetServerEnum(0&, _
100, _
bufptr, _
MAX_PREFERRED_LENGTH, _
dwEntriesread, _
dwTotalentries, _
SV_TYPE_ALL, _
0&, _
dwResumehandle)
'if all goes well
If success = NERR_SUCCESS Then
'loop through the returned data, adding each
'machine to the list
For cnt = 0 To dwEntriesread - 1
'get one chunk of data and cast
'into an SERVER_INFO_100 struct
'in order to add the name to a list
CopyMemory se100, ByVal bufptr + (nStructSize * cnt), nStructSize
List1.AddItem GetPointerToByteStringW(se100.sv100_name)
Next
End If
'clean up regardless of success
Call NetApiBufferFree(bufptr)
'return entries as sign of success
GetServers = dwEntriesread
End Function
Public Function GetPointerToByteStringW(ByVal dwData As Long) As String
Dim tmp() As Byte
Dim tmplen As Long
If dwData <> 0 Then
tmplen = lstrlenW(dwData) * 2
If tmplen <> 0 Then
ReDim tmp(0 To (tmplen - 1)) As Byte
CopyMemory tmp(0), ByVal dwData, tmplen
GetPointerToByteStringW = tmp
End If
End If
End Function |