PowerShell v3 and DNS Queries…

2017-07-27T00:01:04+00:00 January 30th, 2013|Uncategorized|

As I mentioned in last week’s post, “PowerShell v2 and DNS Queries…“, it is much easier to do scripted DNS queries in PowerShell v3 on Windows 8 and Windows Server 2012 than it is in v2 — thanks to the new Resolve-DnsName command.  Following along the same lines as the previous post, and using the exact same example hosts, we can show the same correlations and results for comparison. 

We’ll start off with a request similar to our first nslookup in the previous post, but this time using the Resolve-DnsName command:

And as before, the same holds true with out multi-valued results:

On its face, the results are very similar to nslookup results.  However, since we’re dealing with objects here instead of scraped screen executable output, we can actually manage our results very neatly.  Here’s what I mean, as I enclose the object, and only request the “.IpAddress” from it for my two example hosts:

See how neat, clean, and powerful that is?  This same thing works with other object elements, like “.NameHost“, and such.  By the way, I’ve seen some advice posts out on the ‘Net that advise you to use an increment indicator like this:

(Resolve-DnsName $server_name)

…but that will cause you to only get the first result returned!  And sometimes, that may be what you’re after; but in the case of the multivalued host, that’s probably not what you want.

Now, to contrast last week’s post, I’ll show you how we take the 12-line PowerShell v2 script down to a 3-line PowerShell v3 script:

$ARecord = "labdc1.lab.local"
$NameServerQueried = ""
(Resolve-DnsName -Name $ARecord -Type A -Server $NameServerQueried -ErrorAction SilentlyContinue).IpAddress

 …But of course, it’s only 3 lines because 2 of them are variables; but it’s a fully functional equivalent.  And you can start to see how efficient it can be when looped.  And for the sake of completion of the comparison, here’s the results of my v3 script with the “fakehost” multi-valued host:

…and with the original “labdc1”:

So there you have it.  We love the new commands in PowerShell v3, and they are making our lives soooo much easier (once you know about them).   Now, I’m just waiting for the commands I’ve been asking for… Like Get-MyCoffee… and Get-WorldPeace…. and Solve-GlobalHunger




 (Updated 20130815)

PowerShell v2 and DNS Queries…

2017-07-27T00:01:04+00:00 January 23rd, 2013|Uncategorized|

For this week’s (and next week’s) post, I decided I’d kill a few birds with one stone.  Since it’s “PowerShell month” here at TekTopics.com, and since I’m still making my way through all the differences between PowerShell v2 and v3 (like we all are), I thought I’d tell you about how I just discovered how a relatively simple thing was relatively hard to do in PowerShell v2, and how it got relatively WAY easier in PowerShell v3:  DNS lookups.

Probably like you, I’ve been doing DNS queries for years in all kinds of scripts and languages — like bash, perl, DOS batch files, and of course, PowerShell.  And up until recently, I treated them all pretty much the same — in that I typically just made a system call out to running OS and used the native DNS client query tool, nslookup.  Of course this requires that I grab the output of the tool, scrape out just the information I want (and ignore other data), and continue on to make use of it.

However, in PowerShell v2, the problem is that when trying to grab the desired results back from the system call, the resulting address from the query is not as easy to discern from the “courtesy” information that is returned along with the answer from nslookup.  What I mean is that searching for the string “Address” could get you in trouble, since you end up with two lines that start with “Address” — the one you don’t want (the address of the server that was queried), and the one you want (the query response). 

And in some cases, they could theoretically be the same value, especially if you’re looping through a list of nameservers and query the name of the server you’re querying.  See what I mean in this unfiltered example query and response: 


Note that the record could be multi-valued too, like this example:

So if I just attempt to grab all the strings that match “Address”, as in the following…:

…I could end up with some strange results.  So, instead, I search for all strings in the form of an IP address, and I implement a simple counter to skip the first one, catch any subsequent ones, and split the result to strip out the words.  Here’s the code for my loop:

$ARecord = "fakehost.lab.local"
$NameServerQueried = ""
$FullAddressList = nslookup -type=a $ARecord $NameServerQueried | findstr "
[0-9].[0-9].[0-9].[0-9]" $counter = 0 foreach ($line in $FullAddressList) { $counter = $counter + 1 if ($counter -ne 1) { write "$line" | %{ $_.Split(" ")[2] } } }

…and here are the results, with the query for the multi-valued “fakehost” host record, as in the $ARecord variable as above (inside my Example.ps1 script):

…and with the original “labdc1” nameserver query, as in my first example:

As you can see, DNS queries are do-able in PowerShell v2, but it’s a pain.  The little snippet above should work just fine inside of a larger loop in a validation script, or on its own, for whatever you need to get done.  And I’m sure there are other ways to accomplish the same thing, but this has worked for me in the past (and present) in PowerShell v2. 

Well — now, there’s a new way of getting the same queries done in PowerShell v3, that is much, much, much easier…  And I will jump into that next week.  See you then!

Next week:   The PowerShell v3 way!


PowerShell Basic Commands 101

2017-07-27T00:01:04+00:00 January 16th, 2013|Uncategorized|

It looks like January has turned into “Powershell Month” here at the TekTopics.com! 

And while typically, we write these Powershell-related posts with the assumption that you’re already at least reasonably versed in the language, I thought it might be good to give a few introductory tips to those of you who need the first few basics of Powershell to get you up and running.  Then, you can take these tips and start getting creative with some of the great scripts, loops and commands we’ve talked about here in this blog.

First off, when in the PowerShell command prompt type in “Get-Command” and hit enter:


This will list every PowerShell command available. It is quite lengthy, but can be very helpful if you have the time to scroll through the entire list to discover new and exciting scripting tools.

If you wanted to save this list, you could by outputting it to a file by using the “|” (“pipe”) combined with the “Out-File” command, for example:

Get-Command | Out-File C:Commands.txt

If you are like me and require the list to be sorted by “practical application” then you can sort it by `Module Name’ by simply running:

Get-Command | Sort Module

You can then take it one step further to narrow your search results by filtering by Module name and a “*” (wildcard) as seen here an example of searching for BitLocker:

Get-Command -Module BitLock*

Or if you are looking for a specific command to run to `Enable’ BitLocker:

Get-Command –Module BitLock* -Name Enable* 

From there, if you need usage commands or examples of any newly found Powershell command you can use the “Get-Help” command. The following example would give you helpful information for the “Get-Command” cmdlet as previously mentioned:

Get-Help Get-Command

Or for “Select-String”, the PowerShell equivalent to “FindStr” or the ever-so-popular string search tool called “Grep”:

Get-Help Select-String

One final note to tie this all together: Instead of memorizing the entire cmdlet, module or function names you can use the built-in aliases, which are shorter commands that execute the same command as the long name function, for example: gcm is Get-Command and help is Get-Help

So you could run the following command, which is the same as the above “Get-Help Get-Command”:

help gcm

And you can view the entire list of “Aliases” by running:

gcm -Type Alias

That is all for now! Stay tuned for PowerShell Basic Scripting 101!



Powershell: Script to Easily Find Objects in the SCCM Console

2017-07-27T00:01:04+00:00 January 9th, 2013|Uncategorized|

Recently, I had a need to delete an SCCM advertisement in the SCCM 2007 R2 console, in order to ensure it didn’t run on any of my test machines.  Now, I knew that it wouldn’t run, because it was not being advertised to any collections of which my test machine was a member.  But the advertisement was only a test, and I was trying to clean up after myself.

According to Microsoft (link: http://technet.microsoft.com/en-us/library/bb693527.aspx), the way to delete an advertisement from the SCCM console is to drill down through the console (System Center Configuration Manager / Site Database / Computer Management / Software Distribution / Advertisements) and right-click -> Delete the advertisement.  Normally, this is a pretty straightforward procedure…  IF you know where your advertisement is located.

You see, the SCCM console in which I was working divided the advertisements into sub folders based on the Publishers name, and I could not find a folder for the Advertisement I was trying to delete.



Furthermore, subdividing the Advertisements as such also rendered the “Look For” search field in the console pretty useless; I would have to “Look For” my advertisement in every folder!

SCCM reports can be pretty helpful, and I was able to run a report that gave me just about every piece of data about the advertisement I wanted to delete – except the path to it; the information critical for deleting the advertisement.

A quick Google search led me to this link: http://blog.tyang.org/2011/05/20/powershell-script-to-locate-sccm-objects-in-sccm-console/.  Here, I found the Powershell script that helped me find my elusive advertisement.

The only inputs for this powerful and very useful script are the name of your SCCM site server, and the SCCM object ID, which can easily be found through the “All Advertisements” report in SCCM.  As it turns out, the folder that contained my advertisement had been accidentally moved under another folder. 

It’s great when you find the perfect tool for the job, as I did in this case.  I hope you find it as useful as I did. I intend to keep this one around for future use. 

Thanks, Tao!


Powershell: Get-ADUser Without Errors…

2017-07-27T00:01:04+00:00 January 2nd, 2013|Uncategorized|

I do a lot of scripting of mass-user searches, server and Home Folder validations, etc., where I rely on the Powershell command “Get-ADUser” in my loops.  And this is one of those cases where Powershell is very forgiving; and as such, things like this can be done a handful of different ways.  Of course, some are better than others…

The shortest and easiest form of the command is often fine enough to get the job done, but not always the best in certain situations.  For instance, if you have an IF loop where you are going through an expected list of users (perhaps from an input file) and trying to retrieve a certain attribute for each, you might be inclined to initially write the loop line something like this:

Get-ADUser -Identity $loopUserId

…and this is fairly standard, of course.  In the resulting loop, it would return something like the standard set of attributes in this capture (using a manual query in my lab for this example)

 However, if you are like me, you might occasionally want to watch the output of your scripts while they run; and you prefer to send nice results to screen (as well as to the output logs) for easy debugging and, well, entertainment. 

And this is where the problem arises with the simple format of the command; you soon become annoyed by all the red error messages for the users that have gone missing since your input file was created, as in the case of this intentional search for a non-existent user:

…this is because by default, the Get-ADUser command will give you a nice set of results when it succeeds, but an ugly red message when there is no result.  Yuck.  This simply won’t do; we don’t want to have to panic as if there were an actual *error* every time we get an empty result on each query in the loop!

Instead, we wish to just get a silent, non-return when there are no results.  So, another way to write the same command so that you don’t get any error messages is by using the -Filter option, like this:

Get-ADUser -Filter {SamAccountName -eq $loopUserId}

In this manual example, you can see that the results are the same as if using the earlier format of the command when successful:

…But this time, we get a nice, quiet, non-result in the event of an empty response; as in the case of the same failed search:

Much better!

Now, you can watch your loop output while having a nice… calm… lunch….