Archive for the ‘Functions’ Category

Get MAC Address from IP Address

Saturday, March 18th, 2017

I got a call last week from a member of one the other teams where I work.  He asked, “Do you have a script which will resolve a list of IP Addresses to MAC Addresses?” My answer was, “not yet”.  I did a search and found some very convoluted Pinvoke code. I wanted something easier.

When I automate a task, I begin with the manual steps for the task. To get a MAC address from an IP address, I ping the address, then look at the ARP cache. Get-MACFromIP.ps1 does the same thing,  using the inline script method to make the process run in parallel for speed.  It does not require any administrative rights to run, and is an advanced function.  A use example follows, others are in the code help:

I the use WMI ping method to enable name resolution and the return codes.  The script outputs the IP address, DNS Name (if it can be resolved), MAC address, and the verbose level ping reply.  Capture of the output of the ARP table is based on this post, by Joe Keohan.

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Remove Active Directory Delegations

Saturday, February 25th, 2017

Over time, Active Directory delegations tend to accumulate and drift from the standards in the enterprise.  Removing the delegations for a user or group can be slow, especially if you do it manually.  Microsoft has a good article about this process, but none of the methods I found did what I needed.  I wanted a script which could look at all or selected OUs in AD for a delegation, and then delete them all.

Remove-DelegatedOUPermissions.ps1 is an advanced function which can be used to report and remove assigned delegated permissions from OU objects and containers.  You can choose the domain and searchbase, and you can search for full name or partial matches.  For example, if you wanted to report on or delete the delegations for Site1PWAdmins and Site2PWAdmins, you could simply specify “PWAdmins”.  The search is case-insensitive, and you can search for more than one string by separating your search terms with a comma.

This function always creates a log file.  The default name is derived from the domain name, and the default location is the desktop.  The function requires the ActiveDirectory module, but unlike Set-ACL, it can be used to write permissions in another domain.  It supports WhatIf, and a confirmation is required before you commit changes.  Because it is an advanced function, you can use Get-Help for details about use.

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Get Downtime Using PowerShell

Saturday, February 25th, 2017

I have been having problem with a computer with random reboots, and hanging on restart.  I wanted to know how long the computer had been unavailable.   I decided to use System Event ID 12 as the startup event for the purposes of my calculations.  The script takes these steps: 1) connect to the remote system and get the oldest event from the System Log.  Use this as the earliest start date for queries.  2) Collect all the startup events from user selected date.  3) For each startup event, collect the event immediately previous by record number.  4) Calculate the difference.

Get-DownTime.ps1 is the advanced function which gets the information.  It is the first function I have written which includes A Dot Source Reminder for Advanced Functions.

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Adding Terminal Services Information to User Reports

Saturday, February 4th, 2017

Add-ADTSInfo.ps1 adds TerminalServicesHomeDrive, TerminalServicesHomeDirectory, TerminalServicesProfilePath and AllowLogon as additional members returned by a query of Active Directory user objects.  As you may know, when looking at a user’s properties in the Active Directory Users and Computers MMC there is a tab for these fields.  However, if you look at the properties of a user object, these items simply aren’t there.  There are a few articles and scripts addressing this problem, and you will find that the only way to get the data is by binding to each individual user object and using the a method like this: $ADSIUser.psbase.InvokeGet(‘TerminalServicesProfilePath’).

My script differs from others in that you can pipe an object containing user objects with any properties, and it will add the fields listed above to your results.  I added sorting of the new resulting so that the property names are in order.  This is an advanced function with comment based help.

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Combine CSV Files to XLSX File with Worksheets

Saturday, February 4th, 2017

Three years ago, I posted CombineXLSheets.vbs, a vbScript which allows you to drop and drag Excel spreadsheets onto it and have them combined into a single workbook file with multiple worksheets.  Now that I am working in PowerShell, I have found the need to consolidate CSV files.  Parts of  Combine-CSVFilesToWorksheets.ps1 come from code ported from the vbscript, and this script does a similar job.

I have been experimenting with input validation choices, and you can see some of it here.  One of the things I learned is that a single parameter can have more than one script validations using ValidateScript.  I also decide that the error handling for this is pretty ugly, and moved other input validation into the body of the script.

The script requires that you specify the folder with the CSV files, and the output file for the combined data.  By default the worksheets are named with the base name of the CSV file, and autofit is applied to the columns.  You may optionally turn off autofit, and can delete all of the CSV files when done or the CSV folder itself.  Because this is an advanced function, you can use Get-Help for full help.  The script also supports ShouldProcess (-WhatIf ).

This script requires Excel.

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Export to XLSX without Excel: Export-XLSX.ps1 Revisited and Tweaked

Monday, January 30th, 2017

I often look at the code of others with respect and admiration. Peter Kriegel (Germany) wrote Export-XLSX.ps1, an amazing script which lets you export data into a real XLSX file without Excel being installed. The script also enables you to directly append worksheets to XLXS files. His website,, hasn’t been updated in a while, and the automatic translate function is broken. It isn’t clear to me how to reach Peter, as I typically don’t post the code of others with so few changes, so I want to be clear — this isn’t my work.

I converted the original script to an advanced function, and made sure the Help was functioning right.  The only limitation is with formatting, which means it will look pretty much like a file from Export-CSV.  Nonetheless, if you have scripts running on servers where you really don’t want to install Excel, this is an excellent function to use.  The script is heavily commented and has examples in the help.

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Get the NetBIOS AD Domain Name from the FQDN

Monday, January 30th, 2017

I hate using NameTranslate, because it is a COM object, and because the output is often really hard to get into a clean, trimmed string.  The netBIOS name isn’t a part of the AD domain object, but I suspected that the information could be gotten using a LDAP query.  My searching lead me to a post on StackFlow.  It wasn’t PowerShell, but it did give me an interesting hint.  The filter’s objectcategory was “CrossRef”.  I used this to port the code to PowerShell:

This query is quick, and avoids the formatting problems with NameTranslate.  There is a large table of LDAP queries on TechNet, but this one isn’t in the list.

Convert System.DirectoryServices.SearchResult to a PSObject

Sunday, December 25th, 2016

The ADSI accelerator is fast, and built into PowerShell, unlike the Active Directory Module.  When use it, or the ADSISearcher, you have results which look like this [Image from previous Microsoft URL]:

FindAll Results

Getting the properties out to a file can be tricky.  I wrote two little functions to make this easier:

Get-AllDNSServersInForest.ps1, demonstrates how to use these functions.  It uses the ADSI accelerator to create the ADSI Searcher, then  sends a list of all DNS servers in the forest to Out-Gridview, by using the query “(servicePrincipalName=DNS*)”
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