Is 'X' computer on the network?

[RobDog888]

This code will simulate Network Neighborhood using two combos.
One for the Active Domains and another for the Active Computers
in the selected Domain combo. Maybe it will help you get closer to
a solution.

'IN A MODULE
Option Explicit
 
Public Type SERVER_INFO_100
    sv100_platform_id As Long
    sv100_name As Long
End Type
 
Public Const SV_TYPE_DOMAIN_ENUM         As Long = &H80000000
Public Const SV_TYPE_ALL                 As Long = &HFFFFFFFF
Public Const MAX_PREFERRED_LENGTH As Long = -1
Public Const NERR_SUCCESS As Long = 0&
Public Const ERROR_REQ_NOT_ACCEP = 71&
Public Const ERROR_MORE_DATA As Long = 234&
Public Const NERR_BASE = 2100
Public Const NERR_InvalidComputer = (NERR_BASE + 251)
 
Public 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
 
Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (pTo As Any, uFrom As Any, ByVal lSize As Long)
   
Public Declare Function NetApiBufferFree Lib "netapi32" (ByVal Buffer As Long) As Long
 
Public Declare Function lstrlenW Lib "kernel32" (ByVal lpString As Long) As Long
 
Public Function GetServers(sDomain As String, sType As Long) As String()
 
    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)
    success = NetServerEnum(0&, 100, bufptr, MAX_PREFERRED_LENGTH, dwEntriesread, dwTotalentries, sType, StrPtr(sDomain), dwResumehandle)
    'success = 71 'NO ACTIVE 'DOMAIN'
    If success = NERR_SUCCESS And success <> ERROR_MORE_DATA Then
        Dim compNames() As String
        ReDim compNames(dwEntriesread)
        For Cnt = 0 To dwEntriesread - 1
            CopyMemory se100, ByVal bufptr + (nStructSize * Cnt), nStructSize
            compNames(Cnt) = GetPointerToByteStringW(se100.sv100_name)
            DoEvents
        Next
    End If
    Call NetApiBufferFree(bufptr)
    GetServers = compNames
    
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
 
'BEHIND A FORM WITH TWO COMBOS (cboDomain AND cboComputer)
Private Sub Form_Load()
 
    Dim compNames() As String
    Dim x As Integer
 
    'SETUP THE DOMAIN COMBO BOX
    compNames = GetServers(vbNullString, SV_TYPE_DOMAIN_ENUM)
    For x = LBound(compNames) To UBound(compNames) - 1
        cboDomain.AddItem compNames(x)
    Next
    cboDomain.ListIndex = 0
 
End Sub
 
Private Sub cboDomain_Click()
    'NEED TO CLEAR CBOCOMPUTER AND RELOAD WITH COMPUTERS IN THE NEWLY SELECTED DOMAIN
    'SETUP THE COMPUTER COMBO BOX
    On Error GoTo No_Bugs
    
    Dim compNames() As String
    Dim x As Integer
    
    cboComputer.Clear
    x = 0
    compNames = GetServers(cboDomain.Text, SV_TYPE_ALL)
    If UBound(compNames) > 0 Then
        For x = LBound(compNames) To UBound(compNames) - 1
            cboComputer.AddItem compNames(x)
        Next
        cboComputer.ListIndex = 0
    End If
    Exit Sub
    
No_Bugs:
    If Err.Number = "9" Then
        cboDomain.RemoveItem (cboDomain.ListIndex)
        cboDomain.ListIndex = 0
        compNames = GetServers(cboDomain.Text, SV_TYPE_ALL)
        Resume
    Else
        MsgBox Err.Number & " - " & Err.Description, vbOKOnly + vbExclamation, App.ProductName
    End If
    
End Sub