Jared Heinrichs

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How to figure out what switch port your computer is plugged into

Do you have a live port that wasn’t documented? Normally if you had a huge budget you might have a Fluke device on hand. Unfortunately, not everyone can afford a Fluke Testing Device.

For this article, you will need to have a laptop with Wireshark installed.

Plug in the laptop and start Wireshark. Once you start Wireshark you will want to start the packet capture on the network card that is attached to the port in question.

Once you see that traffic is flowing you should enter the “Filter Expression”:

  • CDP

If you leave Wireshark up and running long enough you will see only the CDP packets start to come in.

The CDP packets will tell you many things. Some of the most useful things are:

  • Device ID – This is the name of the switch
  • Software Version – Firmware Version of the switch
  • Addresses- IP address of the switch
  • Port ID – The switch port the computer is plugged into
  • Cluster Management
  • VTP Domain info
  • VLAN info
  • Duplex Info
  • Management IP address of switch

Here is what you might see:

Once you have one packet captured that is all you will need. Stop the packet capturing and take a look at the first packet.

There will be 4 Main sections of the packet. The section we are going to care about is: “Cisco Discovery Protocol”.

If it isn’t already open please do so now. Scroll down until you see:

Depending on the make and model you might see FastEthernet, GigabitEthernet or just plain Ethernet. The 1/0/4 says the name of the port on the switch!

NOTE- You could also write down the MAC address of the laptop, log into the switch console and look the Mac Address up in the ARP cache. What is nice about the Wireshark method is that you can get this info without having login credentials for the switch!.

Let me know if you have any issues.

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[FIXED] Dism Error: 0xc1420117

I was getting the error message “Error: 0xc1420117” when I tried unmounting a wim file.

To give you a little background about my machine…

It’s is a Windows 2012R2 server with WDS, MDT installed. I installed MDT I needed to install Microsoft ADT which also includes Dism.

If you open a command and run dism the program just runs.

After a little bit of fooling around, I noticed the system had TONS of dism files on it. To resolve the issue you need to run the most up-to-date version. A way to check which dism files are on your computer is to open a command prompt and type:

  • dir C:\dism.exe /s /a

The output will look similar. Notice how the file in the C:\deploymentShare\Servicing\x64 has the most recent file where as the Windows\System32 dism file was made back in 2014.

dism-001

Using the most recent version of dism I then ran the commands:

  • dism /Cleanup-Mountpoints
  • dism /unmount-wim /mountdir:C:\dismmount /discard

NOTE – My mount drive is “C:\Dismount”

Hopefully, this will help you successfully fix your Dism Error: 0xc1420117

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How to fix 8007071a -The remote procedure call was cancelled

Are you getting the error code “8007071a -The remote procedure call was cancelled” when you try and force group policy updates to machines?

8007071a-01

The reason why this is most likely happening is due to the firewall. It is blocking your ability to do this remotely. To allow you to remotely force a gpupdate there are a few services that you need to allow through the firewall.

I would recommend that you do this also through Group Policy! Here are the items you need to open up on the firewall:

  • Remote Scheduled Tasks Management (RPC)
  • Remote Scheduled Tasks Management (RPC-EPMAP)
  • Windows Management Instrumentation (WMI-In)

8007071a-02

 

Apply this to the OU at or above where you are trying to force the update. You now need to tell the person to reboot or open a command prompt and type “gpupdate /force”.

Doing one of those two things will allow you to right click an OU and force update going forward.

8007071a-03

You should now see that the computer will pass the update!

8007071a-04

 

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FIX ColdTurkey doesn’t seem to block websites in Chrome Browser sometimes…

I use a program called “ColdTurkey” to help me block social media during work or study hours. This program typically works well in Internet Explorer however I find that sometimes in Chrome that the page I want to be blocked will sometimes be accessible.

What’s going on with the program?

The Cold Turkey program blocks your access to the websites using your “Hosts” file. It adds a bunch of options to the host file that basically says:

If you want to go to Facebook… Instead of looking up its address through your Internet Service Providers name server, look it up using your locally created host file.

All the sites you block actually get pointed to the Cold Turkey servers instead of the real address of the blocked websites.

Your computer will always look to your host file instead of looking up the name from the name server so it just always seems to work with Internet Explorer but not Chrome.

When troubleshooting the issue I noticed the system was going to the host file (Cold Turkey) location… However, I noticed Chrome was going to the legitimate location. This meant the website could still be accessed.

Because of this troubleshooting, I knew the “issue” was with chrome. It was not with the system or the Cold Turkey software.

After trying several things nothing seemed to work. I did find however a chrome command that seemed to do the trick. If you are using Cold Turkey lots you might want to bookmark the command page for easy access.

In the Chrome Browser you will need to type:

  • chrome://net-internals/#dns

The page will look like this:

chrome-dns-info1

You will need to click the “Clear host cache” button. Once you do this the pages that you had blocked using Cold Turkey will actually be blocked!

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Upgrading Windows 2008R2 DC to Windows 2012R2

When you try to upgrade a Windows 2008R2 Dc to Windows 2012R2 you will notice that you most likely can’t.

Depending on your setup you will most likely get one or two of these errors.

  1. System Devices: Microsoft Emulated S3 Device CapThe S3
    1. This is a non-critical error if you are running the system on a first generation Hyper-v virtual machine. Video driver isn’t supported in Windows 2012r2.
  2. Active Directory on this domain controller does not contain Windows 2012 ADPREP /FORESTPREP updates.
    • The domain needs to be prepped. The link Microsoft provides might give you some insight but does not contain the correct info.
    • The link they provide is: http://go.microsoft.com/fwlink/?linkid=113955 – This link isn’t correct. See info further down in the post.

Here’s what the report looks like. It’s located on your desktop after a failed upgrade.

report-dc-upgrade

As you can see the link only talks about upgrading from really old OS’s to 2008/2008R2 domain controllers and not 2012r2.

At step 4 it says to run adprep from the OS disk to prepare the machine.

  • D:\sources\adprep\adprep /forestprep

ADPrep is no longer found in this directory! It now can be found in:

  • D:\Support\Adprep

forestprep-01

It will run and you will be presented with some info. The main parts are:

  • All Dc’s Must be Windows 2003 or later
  • Can’t be reversed
  • Hit “C” to continue
  • Hit “ENTER” to EXIT

The command output is a few screens in length. Here is the output of the command in my test DC.

forestprep-03

forestprep-04

Now guess what! You also have to upgrade:

  • Domain:
    • adprep /domainprep
  • Group Policy
    • adprep /domainprep /gpprep
  • RoDC
    • adprep /rodcprep

These commands are similar to the first ADPREP command you entered.

Here is the output from those commands:

forestprep-05

The group policy should already be updated but I like to still run the command to make sure:

forestprep-06

Again you shouldn’t need to run this command but I do it anyways to make sure:

forestprep-07

Rerun the install and you will see you can now hit “NEXT” after the compatibility report!

windows28-dc-upgrade

Voila! Your Upgrade is underway!

windows28-dc-upgrade-01

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