Category Archives: sysadmin

Security, sysadmin, VPN, Win10, Windows

Preventing Network and DNS Traffic Leaks – SparkLabs

Preventing Network and DNS Traffic Leaks

A traffic “leak” is when network traffic that should only ever travel over a VPN connection instead travels over the normal network connection, thereby potentially exposing the contents of the traffic to others. This could also potentially expose your true IP address to services you are connecting to. For the vast majority of VPN users network and DNS leaks are not a concern. This article has been written for users who connect to VPN Service Providers, with all traffic directed over the VPN connection, who are concerned about the possibility of a leak occurring.

We are currently working on adding a feature to Viscosity to easily block traffic leaks from occurring. We hope to have such a feature available in a future version of Viscosity, however please be aware that this is not something that will be available soon. In the meantime this article details how you can manually setup Viscosity to prevent traffic leaks from occurring.

Traffic Leak Introduction

Most VPN Service Providers configure their VPN setup to direct all network traffic over a VPN connection while it is active. However in some situations, or for poorly configured setups, network traffic can potentially travel over the normal network connection, even if the VPN connection is active. Traffic leaks typically fall into two categories depending on how you deal with them: network leaks and DNS leaks.

A network leak can occur due to a poorly configured VPN setup (where not all traffic is routed correctly through the VPN connection), or during periods where the VPN connection is not active (for example a dropout has occurred and the VPN connection is in the process of reconnecting). To prevent network leaks it is necessary to ensure that all traffic is correctly flowing through the VPN connection when it is active, and to block network traffic from using the normal network connection when it is not active.

A DNS leak occurs when DNS requests are made to a DNS server on the local network (instead of to a DNS server over the VPN connection) potentially exposing what sites or servers your computer is accessing. This is easily avoided by overriding your local DNS servers with DNS servers that are accessed through the VPN connection.

Checking All Traffic Is Routed Over The VPN Connection

The first step to ensuring that there are no network leaks is checking that all traffic is being directed through your VPN connection while it is connected. This can be done by examining the routing on your computer while connected:

Mac

  1. Connect your VPN connection using Viscosity.
  2. Open the Terminal application. This can be easily done by entering “Terminal” into the Spotlight search field. It can also be found at “/Applications/Utilities/Terminal.app”.
  3. Enter the command “route get 0/1” and press Enter. Make a note of the “interface” entry.
  4. Enter the command “route get 128.0/1” and press Enter. Make a note of the “interface” entry.
  5. If both of the interfaces returned above start with “tun” or “tap”, all traffic is flowing through the VPN connection by default.

Windows

  1. Connect your VPN connection using Viscosity.
  2. Open command prompt. This can be done by pressing Windows + R, type ‘cmd’ into the new dialog and click OK, or go to Start, type ‘cmd’ into search and open Command Prompt.
  3. Enter the command “tracert 1.2.3.4” and press Enter. Let the first hop complete, and take note of the IP Address that appears on the right. You can press ctrl+c to cancel the tracert once the first hop is complete.
  4. Open the Viscosity Details window and select the active connection. If the Client IP that appears in the details window matches, or the first three octets (first three dot parts) of the IP match, all traffic is flowing through the VPN connection by default.
  5. If not, type ‘route print’ into command prompt and locate the IPv4 Route table. If you can locate the IP address returned by tracert under Network Destination, and the Interface value is the same as the Client IP displayed by Viscosity, all traffic is flowing through the VPN connection by default.

If you find that all network traffic isn’t routed through the VPN connection you can change this behaviour like so:

  1. From the Viscosity menu select Preferences to open Viscosity’s Preferences window.
  2. Select your connection from the Connections list and click the Edit button.
  3. Click on the Networking tab. Tick the “Send all traffic over VPN connection” checkbox.
  4. Click the Save button.

Preventing Network Leaks When A Drop-out/Disconnect Occurs

If a VPN connection drops, your computer may use your normal network connection until the VPN connection is re-established. In most cases this is desired behaviour, however to prevent network leaks it is recommended that all traffic is blocked when a drop-out or disconnect occurs. This can most easily be achieved by the scripting technique below. For this technique to work, please ensure the “Reset network interfaces on disconnect” option is disabled under Preferences->Advanced.

Viscosity 1.7.1 and later have a new option that allows you to use OpenVPN scripts without needing to enable Unsafe Commands. These scripts are run elevated which means you do not need to put your credentials into AppleScripts or run Viscosity Windows as an Administrator. For security, the scripts used by this method must be in a designated area in your file system, and must be locked down so they can only be edited by an elevated or administrative user.

Mac

To get started, you will need to enable the AllowOpenVPNScripts option in Viscosity. To enable this option run the following command in the Terminal (/Applications/Utilities/Terminal) application and enter your administrator details when prompted:

/Applications/Viscosity.app/Contents/MacOS/Viscosity -setSecureGlobalSetting YES -setting AllowOpenVPNScripts -value YES

Next, you’ll need to create a script that disables the network connection when a drop-out occurs. You can write a custom shell script in any language supported by macOS, however we recommend using the example script below to get started. This script will automatically disable all active network connections, and it’s not necessary to make any changes to it.

#!/usr/bin/python
import subprocess, re
services = re.findall("\(\d+?\) (.+?)\n\(Hardware Port: (.+?), Device: (.+?)\)\n",
  subprocess.check_output(["/usr/sbin/networksetup", "-listnetworkserviceorder"]))
for service in services:
  if service[1] == "Wi-Fi":
    subprocess.check_output(["/usr/sbin/networksetup", "-setairportpower", service[2], "off"])
  else:
    subprocess.check_output(["/usr/sbin/networksetup", "-setnetworkserviceenabled", service[0], "off"])

To use it copy-paste the code above into a new document in a text editor (such as TextEdit), and save it as a text file to your Desktop with the name “disablenetwork.py”. If using the TextEdit application please make sure it’s saved as plain text by going to the “Format” menu and selecting “Make Plain Text” before saving.

Next you will need to create the folder where the script will be stored, and then copy your script into this location. This can be achieved by running the following commands in the Terminal. Enter your administrator password when requested.

sudo mkdir "/Library/Application Support/ViscosityScripts"
sudo cp ~/Desktop/disablenetwork.py "/Library/Application Support/ViscosityScripts"
sudo chown -R root:wheel "/Library/Application Support/ViscosityScripts"
sudo chmod -R 755 "/Library/Application Support/ViscosityScripts"

Before adding the script to your VPN connection it’s recommend you test it manually to ensure it works as intended. To do this run the following command in the Terminal. If it works your network connection/s should become disabled. If not it means there is a problem in the script or it has not been copied into the correct location.

sudo "/Library/Application Support/ViscosityScripts/disablenetwork.py"

Now you’re ready to add it to your connection in Viscosity. To set the script, edit your connection, go to the Advanced tab, and on a new line add the following command, then click Save:

route-pre-down "/Library/Application\\ Support/ViscosityScripts/disablenetwork.py"

The “route-pre-down” command ensures our script is run before the VPN network’s routing is removed to prevent packet leaks. Other commands that can be used for running scripts at different times include “up”, “down”, and “route-up”. More information on these commands can be found in the Advanced Configuration Commands article.

And that’s it. You can test what happens when your VPN connection drops out by manually disconnecting your VPN connection.

To re-enable a wired (Ethernet) connection after this script has been run simply open up System Preferences and select the “Make Service Active” option. To re-enable a Wi-Fi (Airport) connection simply go to the Wi-Fi icon in the menu bar and select “Turn Wi-Fi On”.

Windows

To get started, you will need to enable the AllowOpenVPNScripts option in Viscosity. To enable this option you will require Administrator rights on your computer. Run the following from Start -> Run, or a command prompt, and click Yes to the User Account Control (UAC) prompt that appears:

"C:\Program Files\Viscosity\Viscosity.exe" SetPref AllowOpenVPNScripts true

Next, you’ll need to create a script that disables the network connection when a drop-out occurs. On Windows you should use a batch (*.bat) script, however any script Windows can run natively is supported. We recommend using the script below which disables your network interface to get started:

netsh interface set interface "Ethernet" admin=DISABLED

To use this script copy-paste the code above into a new document in a text editor (we recommend using Notepad++, but Notepad is fine). You will need to replace “Ethernet” with the name of your network adapter. This could be “Wi-Fi” if you use a wireless network, or “Local Area Connection” on older versions of Windows, however on most modern PCs it is named “Ethernet” for a wired connection. To disable more than one adapter, simply copy-paste the script again onto a new line and replace “Ethernet” with the name of the second adapter.

Once you have finished making changes, save it to your Documents or Desktop as “disable-network.bat”. You will need to enable the interface manually when you want to use your internet connection or reconnect to a VPN.

Once your script is created, copy (do not move or drag/drop the script file) to the following directory. You may have to create this directory first if it does not already exist. To do this, open an Explorer window and navigate to your main disk drive, then go into Program Files, then Common Files. If the Viscosity folder does not exist, right click in empty space, select New -> Folder, click Continue when prompted to provide Administrator rights, then rename the folder ‘Viscosity’. Then enter the Viscosity folder and repeat these steps to create a folder ‘Scripts’.

C:\Program Files\Common Files\Viscosity\Scripts

Replace ‘C:\’ above and in the following steps if your main disk drive where Windows is installed has a different drive letter.

Before adding the script to your VPN connection it’s recommended you test it manually to ensure it works as intended. To do this, open a Command Prompt as Administrator and run the script with the following command. If it works, your network adapter/s should become disabled and you will not longer be able to access the internet. If it does not there is a problem or the script has not been copied to the correct location.

"C:\Program Files\Common Files\Viscosity\Scripts\disable-network.bat"

Now you’re ready to add it to your connection in Viscosity. To set the script, edit your connection, go to the Advanced tab and on a new line add the script command, then click Save. Ensure that the path is complete and quoted, on Windows, backslashes need to be doubled as below.

route-pre-down "C:\\Program Files\\Common Files\\Viscosity\\Scripts\\disable-network.bat"

The “route-pre-down” command ensures our script is run before the VPN network’s routing is removed to prevent packet leaks. Other commands that can be used for running scripts at different times include “up”, “down”, and “route-up”. More information on these commands can be found in the Advanced Configuration Commands article.

And that’s it. You can test what happens when your VPN connection drops out by manually disconnecting your VPN connection.

To re-enable your disabled network adapter/s after this script has been run, go to Control Panel -> Network and Sharing Center -> Change adapter settings (on the left), right click your adapter and select Enable.

Preventing IPv6 Network Leaks

Many modern Internet Service Providers are beginning to offer both IPv4 (IP version 4) and IPv6 (IP version 6) connectivity on their networks. However if your VPN connection is not configured to take this into account it’s possible to leak IPv6 traffic.

Most users are familiar with IPv4 addresses, which are represented as a series of numbers in the format x.x.x.x. IPv4 has long been the default IP version for the Internet and local networks. However the number of available unique IPv4 addresses is limited and has almost run out. IPv6 is designed to solve this problem by offering many more unique addresses. Hence Internet Service Providers are beginning to enable IPv6 on their networks as an eventual replacement for IPv4. An IPv6 address consists of a series of letters and numbers separated by colons, for example 2001:db8:85a3::8a2e:370:7334.

However many VPN Providers have been slow to adopt IPv6 support through their VPN networks. This means that if your ISP provides IPv6, however your VPN connection only supports IPv4 traffic, IPv6 traffic can still go over your normal network connection even while connected to a VPN.

VPN Providers can easily solve this problem, while also preparing for the future, by enabling support for IPv6 traffic through their networks. However if your VPN Provider only supports IPv4 it is possible to block IPv6 traffic while connected to the VPN.

Viscosity provides an option which blocks IPv6 traffic while you are connected to a VPN which does not support IPv6. To enable this option, open Preferences and go to the Advanced Tab, then tick “Block IPv6 traffic while connected to IPv4-only VPN connections”.

You will need to reconnect any connections after changing this option.

If you are unsure if your normal network connection supports IPv6 you can use an IPv6 test connectivity test such as Test IPv6.

Preventing DNS Leaks

DNS leaks can be preventing by ensuring that Viscosity’s DNS support is enabled for your connection, and that a DNS server has been set. For information on how to check that it is enabled and specify DNS servers please see the Configuring DNS and WINS settings article.

Windows Multi-Homed DNS

By default, Windows uses a DNS resolution technique called multi-homed DNS. A very simple explanation of this is Windows will ask every DNS server defined on the system to resolve an address, and send these requests out of ever adapter on the system, and then use the first response. This is quite bad for anonymity and effectively means all DNS lookups leak using Windows default DNS system.

Viscosity for Windows uses it’s own DNS system when you are connected to a VPN to prevent this. However, some users prefer the multi-homed Windows DNS system for various reasons. For this, we have an option available in Preferences -> Advanced called “Use Windows DNS System for Full DNS”. Simply tick this option before connecting to a VPN which uses Full DNS mode and the Windows DNS system will be used instead of Viscosity’s.

Are There Any Third Party Tools For This?

Most firewall software will allow rules to be put in place to block traffic from leaking. Any such rules should block all traffic on the standard network interface with the exception of traffic for the VPN connection itself.

Source: Preventing Network and DNS Traffic Leaks – SparkLabs

PowerShell, sysadmin, Win10, Windows

Error Trapping and Handling in PowerShell

How to use the Trap and Try…Catch…Finally constructs

Don Jones | Jul 20, 2010

Sometimes when something goes wrong in Windows PowerShell, it isn’t a bad thing. That is, there are certain conditions that you can anticipate and potentially deal with, such as a missing file or a computer that can’t be contacted over the network. In response, you might want to prompt the user for an action to take or just log the error so that you can try again later. Windows PowerShell makes this possible through a scheme called error trapping and handling.

First, You Need an Error

To trap and handle an error, you actually need one to occur. Technically, in PowerShell terminology, you need an exception to occur. That can actually be a little tricky to do, believe it or not. For example, try running the following command. It will fail, but pay attention to what happens:

Get-WmiObject Win32_BIOS -comp 'localhost','not-here'

First, you should see the Win32_BIOS instance from your local computer. Then, you should see an error message (unless you actually have a computer named not-here on your network). Think you’ve seen an exception? Wrong. In PowerShell, just because you’ve seen an error message doesn’t mean an exception was created. You can’t trap or handle an error message. You can only trap and handle exceptions.

What you just saw was an example of a non-terminating exception. That is, an exception really did happen, but it wasn’t so bad that the cmdlet needed to stop executing. So the cmdlet basically held the exception deep inside, suppressing its feelings of failure, and continued trying to do what you’d asked. You can’t help the cmdlet if it isn’t going to be more open with its feelings. In other words, you can’t trap and handle non-terminating exceptions. Many of the problems a cmdlet can run into will typically generate a non-terminating exception. That’s because cmdlets don’t want folks to start calling them crybabies, so if something moderately bad happens, they just shut up and keep going.

This cmdlet behavior is controlled by a built-in PowerShell variable named $ErrorActionPreference. You can view its contents by simply typing the variable’s name at the command line:

$ErrorActionPreference

By default, it’s set to Continue, which is what cmdlets do when they encounter a non-terminating error—they keep going. The cmdlets also display error messages by default, but you can shut them off by setting $ErrorActionPreference to SilentlyContinue. Try it:

$ErrorActionPreference = "SilentlyContinue"
Get-WmiObject Win32_BIOS -comp 'localhost','not-here'

This time, the failure occurred but not a word was said about it. Our cmdlet just bit its lip and kept on going, not so much as whimpering about the error. Now, this is where a lot of new PowerShell users go wrong, so I need you to picture me standing up on a table and screaming, “Do not set $ErrorActionPreference to SilentlyContinue just to make the error messages go away.”

Error messages are, by and large, good things. They tell us what’s broken. They’re like the nerves in your fingertips that tell you the stove you’re about to touch is very hot. People who have problems with those nerves often burn themselves. We usually want to see error messages. What we don’t want to see are the error messages that we can anticipate and deal with on our own.

Just Cry Out Loud

When you anticipate a cmdlet running into a problem that you want to deal with, you need to tell that cmdlet to stop bottling up its emotions. You’re not doing this for every cmdlet across the shell, but just for a specific cmdlet that you know you can handle. Since you don’t want to make a global behavior change, you should leave $ErrorActionPreference set to Continue. Instead, you can modify the error action for just one cmdlet.

Every cmdlet in PowerShell supports a set of common parameters, one of which is -ErrorAction (which can be abbreviated -ea). It accepts the same values as $ErrorActionPreference, including stop, which tells the cmdlet to turn a non-terminating exception into a terminating exception—and terminating exceptions are ones you can trap and handle. For this example, you’d run the command

Get-WmiObject Win32_BIOS -comp 'localhost','not-here' -ea stop

Tricky Traps

The first way you can trap an error is to use a Trap construct. Listing 1 shows an example of a trap that’s defined within a function. This code works in PowerShell 1.0 as well as PowerShell 2.0.

Function Do-Something {
  Trap {
    Write-Host 'Error in function' -fore white -back red
    Continue
  }
  Write-Host 'Trying' -fore white -back black
  gwmi Win32_BIOS -comp localhost,not-here -ea stop
  Write-Host 'Tried' -fore white -back black
}

Write-Host 'Starting' -fore white -back green
Do-Something
Write-Host 'Ending' -fore white -back green

Figure 1 shows the output from the code in Listing 1. As you can see, PowerShell first displayed the line Starting. It then executed the function, which displayed the line Trying.

Results from the Trap construct in Listing 1
Figure 1: Results from the Trap construct in Listing 1

Next, PowerShell ran Get-WmiObject, which can be abbreviated as gwmi. It first ran this cmdlet against localhost, and you can see the Win32_BIOS output. But it ran into a problem trying to contact not-here, so an exception occurred. The -ea stop parameter turned that into a terminating exception, so PowerShell looked for a Trap construct within the same scope. It found one inside the function and executed it. That’s why Error in functiondisplayed. The trap finished with the Continue statement, which kept the execution inside the same scope (i.e., inside the function), and Tried was displayed. Finally, the function exited and Ending was displayed.

Traps can be tricky because they are their own scope. Specifically, they’re a child of whatever scope they live in. Consider the modified Trap construct in Listing 2.

Function Do-Something {
  Trap {
    Write-Host 'Error in function' -fore white -back red

# BEGIN CALLOUT A
    $test = 'Two'
# END CALLOUT A
    Continue
  }
  $test = 'One'
  Write-Host "Trying $test" -fore white -back black
  gwmi Win32_BIOS -comp localhost,not-here -ea stop
  Write-Host "Tried $test" -fore white -back black
}

Write-Host 'Starting' -fore white -back green
Do-Something
Write-Host 'Ending' -fore white -back green

Figure 2 shows the output from this version, and I want you to follow the value of the $test variable.

Results from the problematic Trap construct in Listing 2
Figure 2: Results from the problematic Trap construct in Listing 2

The script set the $test variable to One, and that’s displayed in the Trying One output. When the exception occurred, the trap set the $test variable to Two. However, when the trap exited, the output still displayed Tried One. What happened? As a child scope, a trap can access its parent’s variables for reading only. So, when the trap tried to modify $test, it actually created a new local $test variable, which means that $test from the parent scope (i.e., the function) was never changed. This is a real bummer if you want your trap to modify something so that your script can continue. There are ways to remedy this. For example, you can replace the command in callout A in Listing 2 with the following command to change the variable’s contents:

Set-Variable -name test -value 'Two' -scope 1

The -scope parameter treats scope 0 as the local scope, which is within the trap. The next scope up—the trap’s parent—is scope 1. So by changing test in scope 1, you’re modifying the variable that had been set to One. Note that when you use the Set-Variable cmdlet (as well as the other -Variable cmdlets), you don’t use a dollar sign ($) when specifying a variable’s name. 

There’s one more tricky bit about traps that I want to share. Take a look at the alternative Trap construct in Listing 3.

Trap {
  Write-Host 'Error in script' -fore white -back red
  Continue
}
Function Do-Something {
  Trap {
    Write-Host 'Error in function' -fore white -back red
    Break
  }
  Write-Host "Trying" -fore white -back black
  gwmi Win32_BIOS -comp localhost,not-here -ea stop
  Write-Host "Tried" -fore white -back black
}

Write-Host 'Starting' -fore white -back green
Do-Something
Write-Host 'Ending' -fore white -back green

What I’ve done is defined a trap within the script itself, prior to the function’s definition. I’ve also modified the trap within the function to use a Break statement rather than a Continue statement. The Break statement forces the trap to exit the scope in which the error occurred (in this case, the function) and to pass the exception to the parent scope, which is the script. The shell will then look to see if a trap exists in that scope, and I have indeed defined one.

Figure 3 shows what the results look like.

Results from the alternative Trap construct in Listing 3
Figure 3: Results from the alternative Trap construct in Listing 3

When the exception occurred in the function, its trap executed and “broke out of” the function. The exception was passed to the script, so its trap executed. Notice that Tried isn’t displayed. That’s because the function exited before that command could run. All you see is Ending, which is the last line in the script. Although the script’s trap concludes with the Continue statement, all it does is keep the shell’s execution in the same scope (i.e., the script). The shell can’t dive back into the function; it broke out of the function and is out for good unless you call the function afresh.

As this example shows, you can include more than one Trap construct in a script. This means you can set different traps for different types of errors. To get more details, run the command

Help about_Trap

if you’re using PowerShell 2.0. Although PowerShell 1.0 supports the Trap construct, there isn’t a Help file for it. So, if you’re using PowerShell 1.0, you need to access the information at technet.microsoft.com/en-us/library/dd347548.aspx.

Try a Different Approach

Frankly, I find the Trap construct and its scope rules pretty confusing. Fortunately, PowerShell 2.0 offers an alternative: the Try…Catch…Finally construct, which Listing 4 shows.

Try {
  gwmi Win32_BIOS -comp localhost,not-here -ea stop
} Catch {
  Write-Host 'Something bad happened' -fore white -back red
} Finally {
  Write-Host 'Glad that is over'
}

As you can see, you put the command that might fail in the Try block and the command that deals with the failure in the Catch block. You can even add a Finally block that will execute whether or not an error occurred.

Within the Catch block, you can do almost anything, including writing to log files, logging an event log entry, and sending email messages. It’s even possible to create multiple Catch blocks, each of which deals with a certain kind of error. In PowerShell 2.0, you can run the command

Help about_Try_Catch_Finally

for more details.

What’s Your Preference?

In PowerShell 1.0, you must use the Trap construct to trap and handle errors. In PowerShell 2.0, you have a choice between the Trap and Try…Catch…Finally constructs. I prefer using the latter. Not only is the Try…Catch…Finally construct easier to use, but it also keeps the error-handling logic closer to the location of the command that might fail. If you’re using PowerShell 1.0 and you often need to catch and handle exceptions, you might consider upgrading to PowerShell 2.0 so that you can take advantage of this new error trapping and handling tool.

Source: Error Trapping and Handling in PowerShell

PowerShell, sysadmin, Win10, Windows

Hide OneDrive from File Explorer – Power Tips – PowerTips – IDERA Community

Are you tired of OneDrive icons polluting your file explorer tree view? If you don’t use OneDrive, then here are two handy functions that hide and show the OneDrive icons in File Explorer:

function Disable-OneDrive
{
  $regkey1 = 'Registry::HKEY_CLASSES_ROOT\CLSID\{018D5C66-4533-4307-9B53-224DE2ED1FE6}'
  $regkey2 = 'Registry::HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{018D5C66-4533-4307-9B53-224DE2ED1FE6}'
    Set-ItemProperty -Path $regkey1, $regkey2 -Name System.IsPinnedToNameSpaceTree -Value 0
}


function Enable-OneDrive
{
    $regkey1 = 'Registry::HKEY_CLASSES_ROOT\CLSID\{018D5C66-4533-4307-9B53-224DE2ED1FE6}'
    $regkey2 = 'Registry::HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{018D5C66-4533-4307-9B53-224DE2ED1FE6}'
    Set-ItemProperty -Path $regkey1, $regkey2 -Name System.IsPinnedToNameSpaceTree -Value 1
}

Source: Hide OneDrive from File Explorer – Power Tips – PowerTips – IDERA Community

sysadmin, Win10, Windows

Start / Stop / Enable / Disable Terminal services from command line

We can start Terminal Services by running the command given below.

net start TermService

If the service is already running you will get the message ‘The requested service has already been started.‘
Sometimes you may get an error that the service could not be started.

C:\>net start termservice
The Terminal Services service is starting.
The Terminal Services service could not be started.
The service did not report an error.
More help is available by typing NET HELPMSG 3534.

This happens when Terminal Services is disabled through registry hack. You can fix this by running the below registry change command.

reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server" /v TSEnabled /t REG_DWORD /d 1 /f

You need to reboot the computer for the changes to take effect. After reboot terminal services starts automatically or you can start the service using net start command as mentioned above.

How to stop Terminal Services?

Terminal Services can’t be stopped like other services.  You get the below error when you attempt the same.

C:\>net stop termservice
The requested pause or stop is not valid for this service.

How to restart Terminal services?

Since Terminal Services can’t be stopped there is no straightforward way we can do this. Microsoft says this is by design. But in some cases restarting terminal services could be possible by killing the svchost process that runs the terminal services.We can use tasklist and taskkill commands for this.

First get the process id of the terminal services process

 tasklist /svc | findstr /C:TermService

Check if Terminal services is the only service running in this svchost. If the svchost is shared with other services then you can stop reading further. Restarting terminal services is not possible on your machine.

On my system I have got the following output.

C:\>tasklist /svc | findstr /C:TermService
svchost.exe                 1708 DcomLaunch, TermService
C:\>
As you can see DcomLaunch and TermServiceboth share the same svchost process. In this case I can't kill the process as it stops the other service also. (Note that DcomLaunch is an essential service on the system and killing it can even shutdown the system)
In the case of svchost not being shared with any other service you can go ahead and kill TermService process by the following command.
taskkill /F /PID  process_id

How to disable Terminal Services?

We can run the below command to disable terminal services.

sc config TermService start= disabled

How to enable Terminal Services?

sc config TermService start= auto

(or)

sc config TermService start= demand

Source: Start / Stop / Enable / Disable Terminal services from command line

sysadmin

Mozilla GPO – About

Group policy support for Mozilla

Primery project webpage https://mozillagpo.sourceforge.io/

TARGETS

The aim of the project is to provide flexible centralized management of Mozilla software in enterprise environment.

There are other projects with the same goals, but they are either no longer supported (GPO For Firefox last updated in 2014 and incompatible with Firefox Quantum), or are Windows login scripts that modify the user profile (for example FirefoxADM or Firefox ADMX). Both options are unacceptable in the enterprise environment:

  • Time goes and sooner or later it will be necessary to update the browser.
  • Using login scripts is not safe: in modern operating systems logon scripts work asynchronously and user can already open application at the time of their launch.

This project provide autoconfig module that starts with apllication and apply preferences from group policy. Futher read about autoconfig.

FEATURES

 

Source: Mozilla GPO – About