Windows Server core

Windows Server core is minimal installation option for windows server. It has a small footprint which benefits smaller attack surface. There is no GUI in server core and there are many windows features which is not supported in Server core. Windows Server core is more stable as there are few updates needs to be install and less memory, CPU, disk space required to run server core.

Server core doesn’t include below GUI shell packages: -

• 
  Microsoft-Windows-Server-Shell-Package
  
• 
  Microsoft-Windows-Server-Gui-Mgmt-Package
  
• 
  Microsoft-Windows-Server-Gui-RSAT-Package
  
• 
  Microsoft-Windows-Cortana-PAL-Desktop-Package
  

https://docs.microsoft.com/en-us/windows-server/administration/server-core/server-core-roles-and-services

List of Roles and features which is not included in server core: -

https://docs.microsoft.com/en-us/windows-server/administration/server-core/server-core-removed-roles

Installation of Server core is straight forward.

1. 
   Boot using windows server iso file.
   
2. 
   In Setup wizard select windows server 2019 standard or Datacenter (Without Desktop Experience)
   
3. 
   Select Drive
   
4. 
   Installation process will start, and it will take some time to get windows server ready.
   
5. 
   After installation you will prompted for Administrator password change. You must provide complex password else it will keep asking you to change administrator password.
   
6. 
   After completing password change, server installation process completes.
   

After completing installation, you must configure server for e.g. renaming server, network configuration, domain joining etc.

There are many ways of doing it. You can use powershell or sconfig command to configure basic server settings.

If you are using sconfig which is easiest way to then you will get 15 options. Be default Windows provides command prompt after installation. You can change it to powershell.

To use sconfig just type sconfig in command window.

To Change computer name, select option 2. After chaning computer name, you have to reboot server, so settings can take place.

To get server domain joined select option1. It will ask for domain name which you want to join on your network and credentials, so you can add computer to AD.

To Add local administrator, select option 3.

You can select other option based on your requirement.

One main setting is network setting. You can select option 8 (network setting) to configure network settings like IP Address, subnet, gateway and DNS servers.

Apart from sconfig you can choose powershell to change these settings.

Here are few important powershell commands which you can choose.

1. 
   To rename Computer use rename-computer
   
2. 
   To Change IP Address, use New-NetIPaddress
   

New-NetIPaddress -InterfaceIndex 12 -IPAddress 192.168.100.1 -PrefixLength 24 -DefaultGateway 192.168.100.2

To Set DNS servers: -

Set-DNSClientServerAddress –InterfaceIndex 12 -ServerAddresses 192.0.2.4,192.0.2.5

To Check configuration use, Get-Netipinterface

To Check if IPV6 is enabled on NIC use

Get-NetAdapterBinding -ComponentID ms_tcpip6

To Disable IPv6 use

Disable-NetAdapterBinding -Name "Adapter Name" -ComponentID ms_tcpip6

To re-enable it use

Enable-NetAdapterBinding -Name "Adapter Name" -ComponentID ms_tcpip6

To Join Domain or specific workgroup: -

Powershell: - Use Add-computer

Note: - If you are not sure about how to use powershell command then always use get-help command. You can provide -examples switch which as well help you in understanding that how you can use command with correct syntax.

To Add domain account on local administrator group you can use

net localgroup administrators /add \

Server activation: -

Again, you can use sconfig or windows inbuild slmgr vbscipt to active your windows.

In Sconfig you have to select option 11 and with slmgr use below command

cscript windows\system32\slmgr.vbs
:-ato

Managing Windows Server core: -

There are many methods to manage server core. Here is lit of few: -

1. 
   Windows Admin Center
   
2. 
   RSAT Tools
   
3. 
   Windows PowerShell
   
4. 
   Server Manager
   
5. 
   MMC Snap-In
   
6. 
   RDP
   

By default, only one command or PowerShell open in Server core.

I found out a way to open multiple CMD or PowerShell windows. I used taskmgr which open task manager and from there I go to file and run new task. In window type PowerShell or cmd which open new window. By doing this you can have multiple windows.

To enable your local server to be managed by Server Manager running on a remote server, you must enable smremoting. Run below powershell command to enable it on server core: -

Configure-SMRemoting.exe –Enable

You can also use MMC Snap-In to manage server core remotely. MMC Like Computer management allow you to manage server core remotely. For domain joined computer it works fine without doing any extra efforts. But non-domain joined server need some additional steps. You need alternate credential, so you can access server remotely. Use below command to provide alternate credential on remote server and then you can manage server core through MMC.

cmdkey /add: /user: /pass:

If you want to be prompted for a password, omit the /pass option.

You also must allow windows firewall to enable remote management on server core, so you can use remote management tool to manage it remotely.

To Check status of Windows remote management group run below: -

Get-NetFirewallRule -DisplayGroup "Windows Remote management" | ft displaygroup, action

It will show you if remote management group rule is allowed or not. If not, then run below: -

get-netfirewallrule -displaygroup 'Windows Remote management' | enable-netwfirewallrule

To disable it again run below

get-netfirewallrule -displaygroup 'Windows Remote management' | Disable-netwfirewallrule

You can configure firewall rules on per profile basis as well.

To Check what rules are associated with profile run below: -

Get-NetFirewallProfile -Name Public | Get-NetFirewallRule

To Disable a firewall profile run below: -

get-netfirewallprofile | set-netfirewallprofile -enabled $false

There are many rule group for different task. You can enable firewall rules for these rule groups.

Here are few: -

cscript C:\Windows\System32\Scregedit.wsf /ar 0

Most of hardware comes with plug and play. Also installing hardware comes with installation instructions from hardware vendors.

Here are manual steps for hardware drivers which doesn’t come with plug and play.

You must download driver for hardware which you intend to install on server. Copy drivers on server and run below command

Pnputil -I -a

Here driverinf is file the .inf file for the driver

To check what all drivers installed o server run below: -

Sc query type=driver

To disable a device driver run below: -

Sc delete

Here service name is name of service which you get by running sc query type=driver

Making powershell default option on server core: -

By default, when login on server core you get command prompt to work on. But most of time you work with powershell. To make powershell as default you can use modify registry.

Here are steps: -

$path='HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon'

Set-ItemProperty -path $path -Name Shell -value 'Powershell.exe -noexit'

Here are steps to configure memory dump on server core: -

The first step is to manually configure your system failure and recovery options. We must disable automatic managed file option. To do this run follow: -

wmic computersystem set AutomaticManagedPagefile=False

Step 2: Configure the destination path for a memory dump

It is recommended to have page file on partition where OS is installed. To Put page file on another partition we need to modify registry value. Here are steps to configure registry: -

1. 
   Open the command prompt and type regedit. It will open registry editor
   
2. 
   Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CrashControl
   
3. 
   Click Edit > New > String Value
   
4. 
   Name the new value DedicatedDumpFile, and then press ENTER
   
5. 
   Right-click DedicatedDumpFile, and then click Modify.
   
6. 
   In Value data type :\, and then click OK. For e.g. E:\dumpfile.dmp
   
7. 
   Click Edit > New > DWORD Value.
   
8. 
   Type DumpFileSize, and then press ENTER
   
9. 
   Right-click DumpFileSize, and then click Modify.
   
10. 
    In Edit DWORD Value, under Base, click Decimal.
    
11. 
    In Value data, type the appropriate value, and then click OK. The size of the dump file is in megabytes (MB).
    
12. 
    Exit the Registry Editor.
    

wmic RECOVEROS get DebugFilePath

The default destination for DebugFilePath is %systemroot%\memory.dmp. To change the current destination path, run the following command:

wmic RECOVEROS set DebugFilePath =

et to the destination path. For example, the following command sets the memory dump destination path to C:\WINDOWS\MEMORY.DMP:

wmic RECOVEROS set DebugFilePath = C:\WINDOWS\MEMORY.DMP

Determine the type of memory dump to configure for your server. To view the current memory dump type, run the following command:

wmic RECOVEROS get DebugInfoType

To change the current memory dump type, run the following command:

wmic RECOVEROS set DebugInfoType =

can be 0, 1, 2, or 3, as defined below.

• 
  0: Disable the removal of a memory dump.
  
• 
  1: Full memory dump. Records all the contents of system memory when your computer stops unexpectedly. A full memory dump may contain data from processes that were running when the memory dump was collected.
  
• 
  2: Kernel memory dump (default). Records only the kernel memory. This speed up the process of recording information in a log file when your computer stops unexpectedly.
  
• 
  3: Small memory dump. Records the smallest set of useful information that may help identify why your computer stopped unexpectedly.
  
• 
  7: Automatic memory Dump. This is new to windows 10 and new family of windows server.
  

By default, the server automatically restarts after it generates a memory dump. To view the current configuration, run the following command:

wmic RECOVEROS get AutoReboot

If the value for AutoReboot is TRUE, the server will restart automatically after generating a memory dump. No configuration is needed and you can proceed to the next step.

If the value for AutoReboot is FALSE, the server will not restart automatically. Run the following command to change the value:

wmic RECOVEROS set AutoReboot = true

By default, the server overwrites the existing memory dump file when a new one is created. To determine if existing memory dump files are already configured to be overwritten, run the following command:

wmic RECOVEROS get OverwriteExistingDebugFile

If the value is 1, the server will overwrite the existing memory dump file. No configuration is needed, and you can proceed to the next step.

If the value is 0, the server won't overwrite the existing memory dump file. Run the following command to change the value:

wmic RECOVEROS set OverwriteExistingDebugFile = 1

Determine whether an administrative alert is appropriate and set SendAdminAlert accordingly. To view the current value for SendAdminAlert, run the following command:

wmic RECOVEROS get SendAdminAlert

The possible values for SendAdminAlert are TRUE or FALSE. To modify the existing SendAdminAlert value to true, run the following command:

wmic RECOVEROS set SendAdminAlert = true

Step 7: Set the memory dump's page file size

To check the current page file settings, run one of the following commands:

wmic.exe pagefile

or

wmic.exe pagefile list /format:list

For e.g.

You can manually generate a memory dump by using a PS/2 keyboard. This feature is disabled by default, and it is not available for Universal Serial Bus (USB) keyboards.

To enable manual memory dumps by using a PS/2 keyboard, run the following command:

reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\i8042prt\Parameters /v CrashOnCtrlScroll /t REG_DWORD /d 1 /f

To determine if the feature has been enabled properly, run the following command:

Reg query HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ i8042prt \ Parameters / v CrashOnCtrlScroll

You must restart the server for the changes to take effect. You can restart the server by running the following command:

Shutdown / r / t 0

You can generate manual memory dumps with a PS/2 keyboard that is connected to your server by holding the RIGHT CTRL key while pressing the SCROLL LOCK key two times. This makes the computer bug check with error code 0xE2.

Roles and feature on Server core: -

Another most important task on server is to install windows server role and features.

Get-windowsfeature, Install-windowsfeature and uninstall-windowsfeature are major command to manage roles and feature on windows server core.

Here are few examples of these commands:

To get installed roles and feature run below:

get-windowsfeature

get-windowsfeature | where-object{$_.installed -eq $true}

get-windowsgeature | where installed -EQ $true

get-windowsfeature *framework*

To Install .net framework using side by side folder

install-windowsfeature net-framework-core -source D:\Sources\sxs

To Uninstall .net framework

uninstall-windowsfeature net-framework-core

Check if it is removed.

get-windowsfeature *framework*

To restart Computer forcefully

restart-computer -force

To remove binaries as well

When you uninstall windows feature or role, binaries do not remove by default. These unnecessary binaries can take a lot of space. So, if you want to remove these binaries as well then use remove switch as well.

uninstall-windowsfeature net-framework-core -remove

Downloading from internet: -

To download files from internet you can use bits transfer in server core.

Here are few examples: -

To download a file from internet.

start-bitstransfer -source "Download link" -destination C:\

To check status

get-bitstransfer

To suspend a downloading

suspend-bitstransfer

To resume suspended downloading

resume-bitstransfer

Another important task of windows administrators is managing services. Here are few examples to manage services on server core

How to list services

PowerShell Command:

Get-service | Format-table -autosize

How to view a single service

Get-service | where name -eq BITS |Format-list

How to start a single service

Start-Service -name BITS

How to stop a service

Stop-Services -name BITS

How view a Service Startup Type

Get-wmiobject win32_service | where Name -eq bits

How to change the Service Startup Type

Set-Service -name bits -StartupType Automatic

Working with Disk and Volumes: -

To manage disks, we can use get-disk and get-volume commands on server core.

To check available disk

Get-disk

To check volume

Get-Volume

To Install New Disk follow these: -

Check available Disk

Get-Disk

get-disk 0 | initialize-disk

Note: - Here 0 is disk number

After initialization disk will show online.

Create partition

get-disk 0 | new-partition -size 5GB

If you want to assign full space on new partition of disk, then use

get-disk 0 | new-partition -usemaximumsize

To Format new Disk

get-partition -disknumber 0 -partitionnumber 2 | format-volume-filesystem ntfs

To Assign a drive letter

get-partition -disknumber 0 -partitionnumber 2 | set-partition -newdriveletter F

Patch Server core: -

To View Installed update you can use

Get-hotfix or

Systeminfo.exe or

Wmic qfe list

Patch Server Core automatically with Windows Update

Verify the current Windows Update setting:

%systemroot%\system32\Cscript scregedit.wsf /AU /v

To enable automatic updates:

Net stop wuauserv

%systemroot%\system32\Cscript scregedit.wsf /AU 4

Net start wuauserv

To disable automatic updates, run:

Net stop wuauserv

%systemroot%\system32\Cscript scregedit.wsf /AU 1

Net start wuauserv

To force Windows Update to immediately detect and install any available updates

Wuauclt /detectnow

Patch the server manually

Download the update and make it available to the Server Core installation

Wusa .msu /quiet

Without Server Restart

wusa path /quiet /norestart

To uninstall an update manually, run the following command:

Wusa /uninstall .msu /quiet

To Uninstall specific KB

wusa /uninstall /kb:kb4295699 /norestart /quiet

You Can also use sconfig to manage update settings.

Option 5 and 6 are there to manage updates on server core in sconfig command.

Note: - To download a patch from internet use bits transfer commands.

Working with Files: -

To get all availale commands for Item and Content which is used to manage files and file contents

get-command *-item*

get-command *-Content*

To get all items within a directory

get-childitem

To Create new Directory

new-item -itemtype directory -name test -path .\

To Create new file and putting value in that file

new-item -itemtype file -name hello.txt -value "hello world" -path .\test

To get Content of file

get-content -path .\test\hello.txt

To remove item

remove-item -path .\test