Some very handy LDAP queries for user administration

Public Function SearchDistinguishedName(ByVal vSAN)
    ' Function:     SearchDistinguishedName
    ' Description:  Searches the DistinguishedName for a given SamAccountName
    ' Parameters:   ByVal vSAN - The SamAccountName to search
    ' Returns:      The DistinguishedName Name
    Dim oRootDSE, oConnection, oCommand, oRecordSet

    Set oRootDSE = GetObject("LDAP://rootDSE")
    Set oConnection = CreateObject("ADODB.Connection")
    oConnection.Open "Provider=ADsDSOObject;"
    Set oCommand = CreateObject("ADODB.Command")
    oCommand.ActiveConnection = oConnection
    oCommand.CommandText = "<LDAP://" & oRootDSE.get("defaultNamingContext") & _
    	">;(&(objectCategory=User)(samAccountName=" & vSAN & "));distinguishedName;subtree"
    Set oRecordSet = oCommand.Execute
    On Error Resume Next
    SearchDistinguishedName = oRecordSet.Fields("DistinguishedName")
    On Error GoTo 0
    oConnection.Close
    Set oRecordSet = Nothing
    Set oCommand = Nothing
    Set oConnection = Nothing
    Set oRootDSE = Nothing
End Function

Public Function SearchGivenName(ByVal vSAN)
	' Function:     SearchGivenName
	' Description:  Searches the Given Name for a given SamAccountName
	' Parameters:   ByVal vSAN - The SamAccountName to search
	' Returns:      The Given Name
    Dim oRootDSE, oConnection, oCommand, oRecordSet

    Set oRootDSE = GetObject("LDAP://rootDSE")
    Set oConnection = CreateObject("ADODB.Connection")
    oConnection.Open "Provider=ADsDSOObject;"
    Set oCommand = CreateObject("ADODB.Command")
    oCommand.ActiveConnection = oConnection
    oCommand.CommandText = "<LDAP://" & oRootDSE.get("defaultNamingContext") & _
    	">;(&(objectCategory=User)(samAccountName=" & vSAN & "));name;subtree"
    Set oRecordSet = oCommand.Execute
    On Error Resume Next
    SearchGivenName = oRecordSet.Fields("name")
    On Error GoTo 0
    oConnection.Close
    Set oRecordSet = Nothing
    Set oCommand = Nothing
    Set oConnection = Nothing
    Set oRootDSE = Nothing
End Function

Private Function SearchUserID(ByVal vDN)
	' Function:     SearchUserID
	' Description:  Searches the SamAccountName for a given DistinguishedName
	' Parameters:   ByVal vDN - The DistinguishedName to search
	' Returns:      SamAccountName
    Dim oConnection, oCommand, oRecordSet
    
    Set oConnection = CreateObject("ADODB.Connection")
    oConnection.Open "Provider=ADsDSOObject;"
    Set oCommand = CreateObject("ADODB.Command")
    oCommand.ActiveConnection = oConnection
    oCommand.CommandText = "<LDAP://" & vDN & ">;;SAMAccountName"
    Set oRecordSet = oCommand.Execute
    SearchUserID = oRecordSet.Fields("sAMAccountName")
    oConnection.Close
    Set oRecordSet = Nothing
    Set oCommand = Nothing
    Set oConnection = Nothing
End Function