Get Network Address using VBScript


Like everyone else took a boat load of CISCO Networking classes.  Took night classes at the local community college.

Forgot about it.

But, then last week a Network Engineer asked me what is my network address and I just did not know.

Yes, I know how to issue ipconfig and get my IP Address and Subnet mask.

Or on Linux, issue ifconfig.

But, to think one step ahead and get the Network Address and CIDR, my mind just did not want to go down that step.



Opportunity to code…



REM *********************************************************************************************

'   1a)
'   2a)

'   3a)
REM *********************************************************************************************

option explicit

Dim strLog

Dim strIPAddress
Dim strIPSubnet
Dim strCIDR
Dim strNetworkAddress
Dim strAguments

Dim objAguments
Dim iNumberofArgs 

Const CHAR_PERIOD = "."
function getIPAddress

    REM *****************************************************************************
    REM Rob van der Woude's Scripting Page
    REM Win32_NetworkAdapterConfiguration
    REM *****************************************************************************
    Const strQueryNAC = "select * from Win32_NetworkAdapterConfiguration where MACAddress > ''"
    Const WMISERVICE = "winmgmts://./root/CIMV2"

    Dim objWMISvc
    Dim  objRS
    set objWMISvc = GetObject(WMISERVICE)
    if objWMISvc is Nothing then
        strLog = "Unable to Get Object " & WMISERVICE

        WScript.Echo strLog

        WScript.Quit (-1)
    end if

    Set objRS  = objWMISvc.ExecQuery( strQueryNAC, "WQL", 48 )
    Dim objItem
    For Each objItem In objRS
        'IP Address
        If IsArray( objItem.IPAddress ) Then
            If UBound( objItem.IPAddress ) = 0 Then
                strIPAddress = objItem.IPAddress(0)
                strIPAddress = Join( objItem.IPAddress, "," )
            End If
        End If

        'IP Subnet
        If IsArray( objItem.IPSubnet ) Then
            If UBound( objItem.IPSubnet ) = 0 Then
                strIPSubnet = objItem.IPSubnet(0)
                strIPSubnet = Join( objItem.IPSubnet, "," )
            End If
        End If
end function

'*     bitMask(BitNumber)
'*         Returns a number with all bits set to 0 except for the specified bit
Function bitMask(pBit)

    If pBit < 32 Then 

        bitMask = 2 ^ (pBit - 1) 
        bitMask = "&H80000000"

    End If
End Function

Function Dec2Bin(pValue)

    '*     Dec2Bin(AnyNumber)
    '*         Returns a string representing the number in binary.
    Dim TotalBits, i
    strLog = VarType(pValue)
    Select Case VarType(pValue)
        Case vbLong: 
            TotalBits = 32
        Case vbString: 
            TotalBits = 32
        Case vbInteger: 
            TotalBits = 16
        Case vbByte: 
            TotalBits = 8
        Case Else: 
            strLog = "In Function Dec2Bin:: Value passed is " & pValue & vbCrLf
            strLog = strLog + "VarType(pValue) :- " & CSTR(VarType(pValue)) & vbCrLf

            Wscript.Echo strLog
            Err.Raise 13 ' Not a supported type
    End Select

    For i = TotalBits to 1 Step -1
        If pValue And bitMask(i) Then
            Dec2Bin = Dec2Bin + "1" 
            Dec2Bin = Dec2Bin + "0"
        End if

End Function

Function countSpecficChar( strText, chChar)

    Dim iPos
    Dim iLen
    Dim iCharFound
    Dim iCount
    Dim chCharAtPos
    iPos = 1
    iCount = 0

    iLen = len(strText)
    for iPos = 1 to ILen

        'Get character at position
        chCharAtPos = mid(strText, iPos, 1)

        if (chCharAtPos = chChar) then
            iCount = iCount + 1
        end if
    countSpecficChar = iCount

End Function
function getCIDR(strIPSubnet)

    Dim objArr
    Dim strNumber
    Dim iNumber

    Dim strNumberBin

    Dim iNumberofOnes
    Dim iNumberofOnesTotal
    objArr = Split(strIPSubnet, ".")

    iNumberofOnesTotal = 0
    for each strNumber in objArr
        iNumber = CInt(strNumber)
        strNumberBin = Dec2Bin(iNumber)
        iNumberofOnes = countSpecficChar(strNumberBin, "1")
        iNumberofOnesTotal = iNumberofOnesTotal + iNumberofOnes

    getCIDR = iNumberofOnesTotal
end function

function getNetworkAddress(strIPAddress, strIPSubnet)

    Dim objArrIPAddress
    Dim objArrIPSubnet

    Dim iIPAddress
    Dim iIPSubnet
    Dim strNetworkAddress

    Dim id
    Dim idLowerBound
    Dim idUpperBound
    Dim strLogicalAND
    strNetworkAddress = ""

    'Split Numbers into Array   
    objArrIPAddress = Split(strIPAddress, CHAR_PERIOD)
    objArrIPSubnet = Split(strIPSubnet, CHAR_PERIOD)

    id = 0
    'Get Number of Octets
    idLowerBound = LBOUND(objArrIPAddress)
    idUpperBound = UBOUND(objArrIPAddress) 

    'Transverse Numbers
    for id = idLowerBound to idUpperBound
        iIPAddress = CInt(objArrIPAddress(id))
        iIPSubnet = CInt(objArrIPSubnet(id))
        strLogicalAND = ( iIPAddress AND iIPSubnet )
        'If this is not the first number then add delimeter
        if (strNetworkAddress <> "") Then
            strNetworkAddress = strNetworkAddress + CHAR_PERIOD
        end if
        strNetworkAddress = strNetworkAddress + CSTR(strLogicalAND)

    getNetworkAddress = strNetworkAddress
end function

'Get List of Arguments 
set objAguments = WScript.Arguments

iNumberofArgs = objAguments.Count

if (iNumberofArgs >0) and (iNumberofArgs <> 2)  Then

    set objAguments = Nothing

    Wscript.Echo "Expected two arguments IP Address & Subnet Mask"

elseif (iNumberofArgs =2) Then

    strIPAddress = objAguments(0)
    strIPSubnet = objAguments(1)

    call getIPAddress
end if

set objAguments = Nothing

strNetworkAddress = getNetworkAddress(strIPAddress, strIPSubnet)

strCIDR = getCIDR(strIPSubnet)

WScript.Echo "IP Address :- " & strIPAddress

WScript.Echo "IP Subnet  :- " & strIPSubnet

WScript.Echo "Network Address :- " & CSTR(strNetworkAddress)

WScript.Echo "CIDR :- " & CSTR(strCIDR)


There are two type of invocation.

The first one is to pass along the IP Address and Subnet mask.

And, the other is not pass in any arguments and have the script query the system for its IP Address and subnet mask.


cscript networkAddress.vbs


set _IPAddress=
set _IPSubnet=

cscript networkAddress.vbs %_IPAddress% %_IPSubnet%



Source Control



Active Directory ( AD ) – Get User’s Password Expiration Date ( Using VBScript )



Ever so often my Active Directory Account expiration date sneaks up on me.

And, I will like to proactively know ahead of time.



Looked for code and here is one I found from here and there on Net.



REM ***********************************************************

REM Referenced Work: 

'	REM Binding to Active Directory objects with the LDAP provider
'	REm

'	REM Get the Distinguished Name for an Active Directory Object

'	REM How to find the Active Directory Path
'	REM     

'	REM Power ASP VBscript Constants

'	REM VBScript Quit

REM ***********************************************************

REM on error resume next

Function distinguish(strObject, strType) 

    REM Get the Distinguished Name for an Active Directory Object
    Dim objRootDSE
    Dim strDNSDomain
    Dim objConnection
    Dim objCommand
    Dim objRecordSet
    Select case strType 
        Case lcase("computer") 
            strobject = strobject & "$" 
        Case lcase("user") 
        Case lcase("group") 
        Case else 
            Wscript.Echo "Their is an error in the script" 
    End Select 
    ' Determine DNS domain name (this could be hard coded). 
    Set objRootDSE = getObject("LDAP://RootDSE") 
    strDNSDomain = objRootDSE.get("defaultNamingContext") 
    Const ADS_SCOPE_SUBTREE = 2 
    Set objConnection = createObject("ADODB.Connection") 
    Set objCommand = createObject("ADODB.Command") 
    objConnection.Provider = "ADsDSOObject" 
    objConnection.Open "Active Directory Provider" 
    Set objCOmmand.ActiveConnection = objConnection 
    objCommand.CommandText = _ 
    "Select distinguishedname, Name, Location from 'LDAP://" & strDNSDomain & _ 
    "' Where objectClass='" & strType & "' and samaccountname='" & strObject & "'" 
    objCommand.Properties("Page Size") = 1000 
    objCommand.Properties("Searchscope") = ADS_SCOPE_SUBTREE  
    Set objRecordSet = objCommand.execute 
    Do Until objRecordSet.EOF 
       distinguish = objRecordSet.Fields("distinguishedname") 
End Function    

Function Integer8Date(ByVal objDate, ByVal lngBias)

    ' Function to convert Integer8 (64-bit) value to a date, adjusted for
    ' local time zone bias.
    Dim lngAdjust, lngDate, lngHigh, lngLow
    lngAdjust = lngBias
    lngHigh = objDate.HighPart
    lngLow = objdate.LowPart
    ' Account for error in IADsLargeInteger property methods.
    If (lngLow < 0) Then
        lngHigh = lngHigh + 1
    End If
    If (lngHigh = 0) And (lngLow = 0) Then
        lngAdjust = 0
    End If
    lngDate = #1/1/1601# + (((lngHigh * (2 ^ 32)) _
        + lngLow) / 600000000 - lngAdjust) / 1440
    ' Trap error if lngDate is ridiculously huge.
    On Error Resume Next
    Integer8Date = CDate(lngDate)
    If (Err.Number <> 0) Then
        On Error GoTo 0
        Integer8Date = #1/1/1601#
    End If
    On Error GoTo 0
End Function

Function ADPasswordAge

	' First, get the domain policy.


    Dim objRootDSE
    Dim strDNSDomain
    Dim objDomain
    Dim objMaxPwdAge
    Dim lngHighAge
    Dim lngLowAge
    Dim sngMaxPwdAge
    ' Determine domain maximum password age policy in days.
    Set objRootDSE = GetObject("LDAP://RootDSE")
    strDNSDomain = objRootDSE.Get("DefaultNamingContext")
    Set objDomain = GetObject("LDAP://" & strDNSDomain)
    Set objMaxPwdAge = objDomain.MaxPwdAge
    ' Account for bug in IADslargeInteger property methods.
    lngHighAge = objMaxPwdAge.HighPart
    lngLowAge = objMaxPwdAge.LowPart
    If (lngLowAge < 0) Then
        lngHighAge = lngHighAge + 1
    End If
    ' Convert from 100-nanosecond intervals into days.
    sngMaxPwdAge = -((lngHighAge * 2^32) _
                    + lngLowAge)/(600000000 * 1440)

    ADPasswordAge = sngMaxPwdAge
End Function

Function localTimeBiasFromRegistry()

	' Retrieve user password information.
	' The pwdLastSet attribute should always have a value assigned,
	' but other Integer8 attributes representing dates could be "Null".

    dim lngBias
    ' Obtain local time zone bias from machine registry.
    ' This bias changes with Daylight Savings Time.
    Dim objShell
    Dim lngBiasKey
    Dim k
	Const REGISTRY_KEY_ActiveTimeBias = "HKLM\System\CurrentControlSet\Control\TimeZoneInformation\ActiveTimeBias"
    Set objShell = CreateObject("Wscript.Shell")
	lngBiasKey = objShell.RegRead( REGISTRY_KEY_ActiveTimeBias)
    If (UCase(TypeName(lngBiasKey)) = "LONG") Then
        lngBias = lngBiasKey
    ElseIf (UCase(TypeName(lngBiasKey)) = "VARIANT()") Then
        lngBias = 0
        For k = 0 To UBound(lngBiasKey)
            lngBias = lngBias + (lngBiasKey(k) * 256^k)
    End If  
    localTimeBiasFromRegistry = lngBias

end function

function getUsername()

	Dim strUserName

	set objNetwork = CreateObject("WScript.Network")

		strUserName = objNetwork.UserName
	set objNetwork = Nothing

	getUsername = strUserName

end function

Dim objUser
Dim maxPwdAge
Dim numDays

Dim strDomainDN
Dim strOrganizationUnit
Dim strRelativeDistinguishedNameofContainer
Dim strDistinguishedNameSuffix
Dim strDistinguishedName
Dim strUser
Dim objNetwork
Dim strUserName
Dim strUserDN

Dim strLog

dim objDatePwdLastSet
dim dtmPwdLastSet
dim lngBias

Dim sngMaxPwdAge

Dim dtPasswordExpiry  

Dim strLDAP


strUserName = getUsername()

strDistinguishedName = distinguish(strUserName, "user")                         

strUserDN = PROTOCOL_IDENTIFIER_LDAP & strDistinguishedName
strLog = "strUserDN :- " + strUserDN

WScript.Echo strLog

strLDAP = strUserDN

Set objUser = GetObject(strUserDN)

if (objUser is Nothing) Then

    strLog = "GetObject failed on " & strLDAP
    WScript.Echo strLog 

    strLog = "Err.Number is " _
                    & CSTR(Err.Number) _
                    & " & " _
                    & "Error Description is " & Err.Description _
                    & vbCr                      
    WScript.Echo strLog


end if

lngBias = localTimeBiasFromRegistry

If (TypeName(objUser.pwdLastSet) = "Object") Then

    Set objDatePwdLastSet = objUser.pwdLastSet
    dtmPwdLastSet = Integer8Date(objDatePwdLastSet, lngBias)

    dtmPwdLastSet = #1/1/1601#
End If

strLog = "dtPwdLastSet :- " & CSTR(dtmPwdLastSet)

WScript.Echo strLog

sngMaxPwdAge = ADPasswordAge()

strLog = "sngMaxPwdAge :- " & CSTR(sngMaxPwdAge)
WScript.Echo strLog

dtPasswordExpiry = DateAdd("d",sngMaxPwdAge,dtmPwdLastSet) 

strLog = "dtPasswordExpiry " & CSTR(dtPasswordExpiry)
WScript.Echo strLog

' Clean up.
Set objUser = Nothing

Set maxPwdAge = Nothing


cscript passwordExpirationDate.vbs


Output – Image #1

Output – Image #2





Dedicated To …

  1. Richard Mueller ( Microsoft MVP )
  2. Devin H.
    • Get the Distinguished Name for an Active Directory Object

Windows – Windows Script Host/VBScript – Getting Full Name of Network User


Here I am with a Network Logon, but no corresponding Fullname.


Windows AD Tools

Depending on the version of Windows, we can quickly put together a script for getting the information.

      dsquery user -name joe | dsget user -display


If invalid username, you will get :

    dsget failed:'Target object for this command' is missing


If valid user, you will get something such as :

  Adeniji, Daniel




Here is a VBscript for doing same:



Option Explicit
Dim strADDomain
Dim strUserName
Dim strUserNameCurrent
Dim objWshShell
Dim strObjectData
Dim strNameNotFound
Dim iCommandLineArgCount
Dim objUser

Const CommandLineArgCountExpected = 1
Const ERR_InvalidProcedureCallORArgument = 5

Const OBJECT_REF_SYNTAX = "WinNT://{0}/{1}"
Const ERR_NAME_NOT_FOUND = "Not not found Domain {0} / User {1}"

rem SQL string formatting in VBScript
function fmt(str, args())
   dim res, i
   res = str
   for i = 0 to ubound(args)
      res = replace(res, chr(123) & cstr(i) & chr(125), cstr(args(i)))
   fmt = res
end function

REM *******************************************************************
Rem MS Windows Shell Environment Variables
REM *******************************************************************
Set objWshShell = WScript.CreateObject( "WScript.Shell" )

	strADDomain = objWshShell.ExpandEnvironmentStrings( "%USERDOMAIN%" )

	strUserNameCurrent = objWshShell.ExpandEnvironmentStrings( "%USERNAME%" )

set objWSHShell = Nothing

REM *******************************************************************
Rem Get Command Line Arguments
REM *******************************************************************
iCommandLineArgCount = WScript.Arguments.Count

if (iCommandLineArgCount = CommandLineArgCountExpected) Then

	strUserName = WScript.Arguments.Item(0)


	Err.Raise ERR_InvalidProcedureCallORArgument ' Invalid procedure call or argument

end if

REM *******************************************************************
Rem If arguments not passed in, then assume for current user
REM *******************************************************************
if (strUserName = "") Then

	strUserName = strUserNameCurrent

end if

rem strObjectData = "WinNT://" & strADDomain & "/" & strUserName
strObjectData = fmt(OBJECT_REF_SYNTAX, array(strADDomain, strUserName))

rem (null): The network path was not found.
on error resume next

	Set objUser = GetObject(strObjectData)

on error goto 0

rem display full name
if IsObject(objUser) Then

	Wscript.Echo objUser.FullName


	strNameNotFound = fmt(ERR_NAME_NOT_FOUND, array(strADDomain, strUserName))

	Wscript.Echo strNameNotFound

end if	

rem free object
if IsObject(objUser) Then

	Set objUser = Nothing

end if



To try things out:


    cscript getUserFullName.vbs dadeniji









How poetic justice is that?

I bemoaned “On error resume next”, Microsoft – Classic ASP – Error Suppressed, barely a week gone by.  And, now I need it to avoid a missing AD Entry warning.

But, nevertheless when used, quickly close it out with an “on error goto 0“.


Microsoft – Classic ASP – Error Suppressed


The last few weeks I have been battling with a Vendor application that uses a mix of Classic ASP and ASP.Net.  Not to keep the beating to myself, I will like to share some of my bruised ego.



Classic ASP

We will focus on the Classic ASP code.  There are many reasons for this singular focus; and inclusive:

  • Historical
    • Classic ASP was introduced in 1996
    • It was Microsoft’s first server side scripting engine for generating web pages
  • Tooling
    • It is based on VBScript and JScript
    • ASP 2.0 provided six built-in objects: Application, ASPError, Request, Response, Server, and Session
    • It has being in support for accessing COM and Dlls


As a tool developed in 1996,  almost 20 years ago, it is increasingly difficult to elegantly support it.


Sample Code

Let us create a sample app


Err Suppressed
<@% Page Language=VBScript 	Explicit=True Debug=True %>
<% Response.Buffer = True %>
<!--#include file="errorHandler/"-->


	Const ERR_HANDLER_CUSTOMIZED = "/errorHandler/errorHandler500Customized.asp"


	dim strDate
	dim iNumberofEntries
	dim objDictModule
	dim allKeys
	dim allItems
	dim dictKey
	dim dictItem
	Dim i
	Dim iMax	

	dim objNullObject
	dim objErr

	dim numerator
	dim divisor
	dim result

	dim strItem
	dim iErrType

        dim strPagename

        strPagename = Request.ServerVariables("SCRIPT_NAME") 

        if (ON_ERROR_RESUME_NEXT) then

		On error resume next

	end if


	if (iErrType = ERR_TYPE_DIVIDEBYZERO) then

		numerator = 1000
		divisor = 0
		result = a / b



	end if

	set objErr = Err

	set objDictModule = getErrorObjectAsDictionary(objErr)

	set Session(ERR_OBJECT_CUSTOM) = objDictModule

	if ( (Err.Number <> 0) and (ON_ERROR_PROCEED_ERRORHANDLERPAGE = true) ) Then

           'store calling page name
           Session(ERR_OBJECT_CUSTOM).add "Err.Referrer", strPagename

           Response.Redirect ERR_HANDLER_CUSTOMIZED

	end if



In the code above, we have intentionally added the usual suspects; that is things we know will cause trouble:

  • Divide by 0
  • Reference a null object ( objNullObject.Sleep )


IIS Configuration – ASP

Let us make sure that IIS is sufficiently for debugging ASP.

  • Via “Control Panel” \ “Administrative Tools” \ Internet Information Services (IIS) Manager
    • In the left panel, Under Sites, Select the Web Site
    • In the right panel, make sure that the Features View is active
    • In the Features view, within the IIS panel, select ASP


Features View



ASP Configuration



The important configurable items are:

  • Debugging Properties – Set to True
    • Calculate Line Numbers
    • Catch COM Component Exceptions
    • Enable Client-side debugging
    • Enable Log Error Requests
    • Enable Server-side Debugging
    • Log Errors to NT Log
    • Send Errors to Browser
  • Script Language
    • VBScript


Error Message

Upon launching a Web Browser, IE in this case, we run into a ditch.

Here is what we get:



Not a very intuitive error message as we had “Show Friendly HTTP error messages“.

Current Setting:



More Intuitive Message

Via “Internet Options”, we turned off “Show friendly HTTP error messages”.

And, we now have a good error number,  error message, and source file name & offending line number.




 IIS Log

IIS Logs also contain helpful data.



Our IIS Log contains definite and helpful error; here they are:

  • We have .Net CLR2 and CLR3 installed
  • Our error line is 57
  • Our error code is 800a006
  • Our error description is Overflow



Sample Code – “On Error Resume Next”

Let us change the code a bit by setting “On error resume next


    'Const ON_ERROR_RESUME_NEXT = false
     Const ON_ERROR_RESUME_NEXT = true

Once we set “On error resume next”, our error is no longer visible …

Browser – IE


Browser - IISLog

Checked IISLog, and no errors registered


Error Handling

It is obvious that silencing our errors is a bit problematic; as we still have them, but we are not aware of them. Furthermore, the work we greatly want to do, is yet undone. Let us handle our error, and send the user to an informative error page.




As we have now indicated that we want to handle our error, though it is silent, we wrote additional modules:


Classic ASP supports a couple of ways to organize code, source code modules & Com components.  In this post, we will take the quick and simple path of having the code in an included file (errorhandler/

Though not required, we placed in its own folder, as well.


  <!--#include file="errorHandler/"-->



Here is our included file.


Const ERR_OBJECT_CUSTOM = "customErrorCollection"

Function getErrorObjectAsDictionary (objErr)

     Dim objList
     Dim objASPError

     Set objList = CreateObject("Scripting.Dictionary")
     objList.add "Err.Number", objErr.Number
     objList.add "Err.Description", objErr.Description

     set objASPError = Server.GetLastError()

     objList.add "ASPError.ASPCode", objASPError.ASPCode
     objList.add "ASPError.ASPDescription", objASPError.ASPDescription
     objList.add "ASPError.Description", objASPError.Description
     objList.add "ASPError.Source", objASPError.Source
     objList.add "ASPError.Number", objASPError.Number
     objList.add "ASPError.File", objASPError.File
     objList.add "ASPError.Line", objASPError.Line

     rem we used set as objList is an object and not a simple datatype (int\string)
     Set getErrorObjectAsDictionary = objList

End Function



The is an interesting code-line:

  • We are a generic collection object (Scripting.Dictionary)
  • We captured both the err.number and err.description properties into our collection
  • We also performed a Server.GetLastError call and captured the resultant object’s property, as well
  • Noticed that we used set at the end of the function to return a complex object





Err Handler - 500 - Customized

<@% Page Language=VBScript 	Explicit=True Debug=True	EnableSessionState=True	%>
<!--#include file=""-->



	 Dim objError
	 Dim objDictModule
	 Dim errNumber
	 Dim errDescription

	 Dim objErr
	 Dim objErrDict

	 Dim strBuffer

<table border="1">
<table border="0" width="653">
<tr style="background-color: #ff9900;">
<td colspan=3 col align='center'><strong>Error Items</strong></td>
<tr style="background-color: Gainsboro;">
	Access Err Object
<tr style="background-color: beige;">
<td><strong><%= CSTR(Err.Number) %></strong></td>
<tr style="background-color: beige;">
<td><strong><%= Err.Description %></strong></td>

	strBuffer = ""
	CONST COLOR_ROW = "beige"
	CONST COLOR_ROW_ALTERNATE = "blanchedalmond"

	Dim strRowColor
	Dim strItem

	If isObject(Session(ERR_OBJECT_CUSTOM)) = false then


		set objDictModule = Session(ERR_OBJECT_CUSTOM)

		if (objDictModule is Nothing) Then


			'retrieve all the keys and items from the Dictionary and print them out
			allKeys = objDictModule.Keys   'Get all the keys into an array
			allItems = objDictModule.Items 'Get all the items into an array 

			For i = 0 To objDictModule.Count - 1 'Iterate through the array

			  dictKey = allKeys(i)   'This is the key value
			  dictItem = allItems(i) 'This is the item value

			  if ( (i mod 2) = 0) then
				strRowColor = COLOR_ROW
			    strRowColor = COLOR_ROW_ALTERNATE
			  end if	

			  strItem = "
<tr style='background-color: " & strRowColor & "';>"
			  strBuffer = strBuffer & strItem

			  strItem = "
<td>" & cstr(i+1) & "</td>
			  strBuffer = strBuffer & strItem

			  strItem = "
<td>" & dictKey & "</td>
			  strBuffer = strBuffer & strItem

			  strItem = "
<td>" & dictItem & "</td>
			  strBuffer = strBuffer & strItem

			  strItem = "</tr>
			  strBuffer = strBuffer & strItem


		end if

	end if

	Response.Write strBuffer






Here is a quick explanation

  • We checked Err.Number and Err.Description
  • We checked the Session Object that was “set” in the previous page
  • Notice the use of IsObject to ensure that our session variable is previously set



Browser Output:





From the screen above, we will notice a few things:

  • We lost our original error; that is why when the new page calls err.number and err.description we have 0 and empty
  • Thankfully, our session data was preserved



It appears that when we use “on error resume next” and post to another page, our err object ( Err.Number and Err.Description ) is automatically reset.


Application Level



From the example above, we can see that the “on error resume next” statement, prevents error trapping through code.

What about error trapping that is implicitly handled in web.config



Edit Custom Error Page:

Here is how to configure Error Page via “IIS Management Console”




Error Message

In our case, we tweaked our website’s configuration quite a bit. We reviewed and played around with the Application Pool and the actual web site.

Error Text:

Error Message: This site is in an application pool that is running in Classic mode. When running in this mode, custom errors apply to all content except ASP.Net content.

Error Image:



The error message hints that we need to change our Application Pool’s managed pipeline from Classic to Integrated.


Application Pool

ApplicationPool - MangedPipelineMode - Integrated


Error Pages – Feature Settings

It is also important that we set/review the default “Error Pages” settings.


CustomErrorPage - Edit Features


We want to set “Error Page Settings” / “Custom Error Pages” to “Custom error pages”.

If set to :

  • Detailed errors (everyone sees the detailed errors)
  • Detailed errors for local requests and custom error pages for remote requests ( when viewed locally on the web server one sees the detailed error message; and when viewed away from the web server, one sees our custom error page)


Source Code

Here is what our web.config looks like:


<?xml version="1.0" encoding="UTF-8"?>


                <add value="ErrSupressed.asp" />

                <remove path="*" />
                <add path="*">
                        <add provider="ASP" verbosity="Verbose" />
                        <add provider="ASPNET" areas="Infrastructure,Module,Page,AppServices" verbosity="Verbose" />
                        <add provider="ISAPI Extension" verbosity="Verbose" />
                        <add provider="WWW Server" areas="Authentication,Security,Filter,StaticFile,CGI,Compression,Cache,RequestNotifications,Module,FastCGI" verbosity="Verbose" />
                    <failureDefinitions timeTaken="00:00:00" statusCodes="100-999" />

        <httpErrors errorMode="Custom">
            <remove statusCode="500" subStatusCode="-1" />





There are a few things going on in the web.config file indicated above; and those are:

  • We are using our great friend – traceFailedRequests; whenever an error occurs an XML file is generated
  • We are using trapping on HTTPErrors
    • We are using ErrorMode is Custom :- This is we have our our own custom code
    • HTTP Error = 500
      • We call /errorHandler/errorHandler500Customized.asp
      • responseMode = ExecuteURL



Once we add a web.config page, we will have instituted an Application wide error handling pathway.

The Application wide pathway will work for all cases, except when “on error resume next” is in-effect.


How do we test?

How do we investigate whether we can handle errors implicitly?

We will remove “on error resume next”.

rem Const ON_ERROR_RESUME_NEXT = true


Just-In-Time Debugger:



We will not trod down the Debugging trek; and so we will skip initiating the debugger by choosing “No, cancel debugging“.


Here is what we see when a code error and IIS itself triggers our error page




We can see that we have lost useful error data.  Earlier we preserved them by saving them to session variables and then transferring processing to the Error Page.

Spent all weekend trying to get to them when IIS auto-invokes the error page, but not smart enough.


On error goto 0

“On error goto 0” return us back to sanity.  I will suggest that for each “on error resume next”, a corresponding  “on error goto 0” be added as a complement.


Exception Handling

Modern languages idiom rely on try/catch/finally exception paradigm.


Source Control


To make it easier to share and review our simple App, we have place it on Github.


Where did Classic ASP come from?

Accordingly to Wikipedia, Classic ASP was introduced as part of NT Option Pack in 1996.  And, discontinued 4 years later in 2000.

NT Option Pack is one of the most important product release from Microsoft.  Keeping in mind that it was a midterm release between Windows NT 4.0 and Windows 2000, and Microsoft was trying to stem the tide of competing products; and so everything along with the Kitchen Sink and the proverbial workman’s hamburger was included.

According to Windows NT Option Pack, here is what was bundled within it:

  • Certificate Server – Microsoft Certificate Server provides customization services for issuing and managing certificates used in software security systems employing public-key cryptography.
  • FrontPage Server Extensions
  • Index Server – It allows you to easily perform full-text searches and retrieve all types of information from any Web browser.
  • Internet Connection Services for RAS – Remote Access Service
  • Internet Information Server (IIS) version 4.0
  • Mail and News Services – Microsoft SMTP Service uses the standard Internet protocol Simple Mail Transfer Protocol (SMTP) to transport and deliver messages
  • The Microsoft NNTP Service – Newsgroup
  • The Microsoft Data Access Components (MDAC) – ActiveX Data Objects and the Microsoft Access driver
  • Microsoft Management Console (MMC) – Uniform interface for managing server application
  • Microsoft Message Queue Server (MSMQ) – communicate with other application programs quickly, reliably, and asynchronously by sending and receiving messages
  • Microsoft Transaction Server (MTS) – component-based transaction processing system for developing, deploying, and managing high-performance, scalable, and robust applications
  • Site Server – Comprehensive Web site environment for enhancing, deploying, and managing rich intranet and Internet Web sites
  • Microsoft SNA Server – comprehensive gateway and application integration platform that enables communications with midrange ( AS/40)0 and mainframe systems
  • Windows Script Host – a language-independent scripting host for ActiveX™ scripting engines



Once again, I will dedicate this post to a public commit-er, former Microsoft engineer, Eric Lippert. I referenced an important blog post by him in the Reference section below.

Eric blogs @ and he has an interesting post @ “Eric Lippert Dissects CVE-2014-6332, a 19 year-old Microsoft bug” ( )



For a product released in 1996 and deprecated in 2000; ASP has obvious staying power.

For the sake of the numerous companies and products that continue to rely on it, I wish keen attention, knowledge and courage.

For sustenance engineers, keep an eye out for “On error resume next“.



Reference – httpErrors and customErrors




Blog and Q/A


IIS – Custom Errors – Sample Code




3rd Party Vendor



Storing & Transfering Data


Collection Object

Dictionary Object


Session Variables





Best Practices

ASP Error Handling – Reference


ASP Error Handling – Sample


Including File


Test Object




Error Handling


Page Transition

Move to new page





“On Error Resume Next ” Stories