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Active Directory / Microsoft / Pi-Hole / Server 2019

Use Pi-hole with Microsoft Active Directory

- by Vikash Jhagroe - 23 Comments.
Reading Time: 6 minutes

I’m a big fan of Pi-hole and have been using it to get rid of advertisement and tracking. Check my blogpost here if you want to know how to set Pi-hole up. It’s an amazing piece of software to protect your online privacy and provide network wide ad-blocking. In my day job I’m an IT-consultant for enterprise IT-solutions and in this post I will show you how to use Pi-hole with Microsoft Active Directory and protect all your domain joined clients from advertisement, tracking and also keep your clients secure from those malware websites.

Of course, you need to test this extensively before rolling it out in your infrastructure. I cannot stress this enough. The solution described in this blogpost did not show any kind of strange unexpected behaviour in my testlab but every infrastructure is different. Especially with endusers and applications there may be some challenges. So test before you implement!

Requirements

Microsoft Active Directory depends on Active Directory-Integrated DNS Service and Active Directory-Integrated DHCP Service. In this scenario all your domain joined clients are getting their IP-addresses and DNS settings from the Microsoft DHCP server. The DNS settings is used by the domain joined clients to talk to the Active Directory for DNS lookups and Active Directory related tasks. My testlab is running on Windows Server 2019 Active Directory and DNS Service, but this should also work if you are running a Windows Server 2016 environment. The requirement list is:

  • Microsoft Windows Server 2019
  • Microsoft Active Directory 2019
  • Microsoft Active Directory-Integrated DNS 2019
  • Microsoft Active Directory-Integrated DHCP Server 2019
  • Pi-hole Server
  • Domain joined client(s)

Let’s get started

They key Pi-hole feature we will be using in order to get this working is called Conditional Forwarding. I will explain in this post later on how we will use this feature.

DHCP Server settings

My DHCP Server is running on my Active Directory Domain controller. I’m sure a lot of you have the same setup which is fine. In the DHCP Server we have to specify certain options like DNS Servers and DNS Domain Name. My DHCP server is running on IP-address 192.168.130.10. My DNS Domain Name is vikash.nl. For DNS Servers fill in the IP-address of your Pi-hole Server. My Pi-hole server is running on IP-address 192.168.100.21.

On your DHCP server open the management console for DHCP Server and expand the scope options. Make sure the values match your network infrastructure:

Pi-hole Server settings

Now I will show you how to use Pi-hole with Microsoft Active Directory. The idea here is provide the Pi-hole Server as the DNS server to your domain joined clients. Then in the Pi-hole Server settings we will enable the option called Conditional Forwarding. Here we have to enter the IP-address of our Active Directory-Integrated DHCP server and also a Local Domain Name. This local domain name has to be your Active Directory name. In my case that is vikash.nl. What will happen now is that if the Pi-hole gets DNS requests from clients that need to resolve something.vikash.nl it will forward that request to our DHCP server which is also our Active Directory Domain controller. This makes sure that all the Active Directory related communications between my domain joined clients and Active Directory are completed successfully.

On the Pi-hole server go to Settings and select the DNS tab:

As you can see in the screenshot above I am using Cloudflare DNS Servers as my Upstream DNS. You can use any DNS Server as your upstream DNS. This basically means that for all DNS requests not related to vikash.nl the Pi-hole server will resolve those using Cloudflare. That is exactly what we want because it will make sure that internet is still working for all our domain joined clients. At the same time we will be able to see all the DNS requests in the Pi-hole Server Query Log for every client. This gives us control to protect our domain joined clients from ads, tracking or even malware.

In the DNS tab scroll to the bottom of the page and enter the DHCP server IP-address and the Local Domain Name. My DHCP server is 192.168.130.10 and my Local Domain Name is vikash.nl. Check your network infrastructure for your specific settings and click Save:

Testing

Now let’s make sure that everything works. First we will check that the correct DHCP settings are distributed to a client we want to join to the domain vikash.nl. I will use a Windows Server 2019 as client with the name vdi01.

Check IP-address

Open up a command prompt on the machine and make sure that the client is getting the correct settings from the DHCP server:

As you can see in the screenshot above the client is getting the DNS Domain Name and the DNS Server settings according to our scope options in the DHCP server. Check that the client is not already domain joined:

Join the client to the domain

Next step is to join the client (my vdi01) to my domain vikash.nl. Click in the Server Manager on WORKGROUP and then click on Change in the window that pops up:

Select the Domain option here and enter your domain name. Remember that this must be the same as DNS Domain Name entered in the DHCP Scope options and in the Conditional Forwarding on the Pi-hole. In my case this is vikash.nl. Then click on OK.

Windows will prompt you to enter Domain credentials which are allowed to do a domain join. In my testlab I use the domain administrator account for that. Enter the credentials and click on OK:

You will get a prompt from Windows telling you that the domain join was completed successfully. It looks like everything is working :). Click on OK and reboot you client.

After the client reboots login using a domain account:

Check that everything is ok and the client is a member of the domain:

Check Pi-hole Query Log

We can see the magic happening when we check the Query Log on our Pi-hole Server. Open the admin page of Pi-hole server and select the Query Log in the left menu:

As you can see in the screenshot above my client with IP-address 192.168.130.211 (vdi01.vikash.nl) is able to resolve internet queries as wel as queries related to my domain vikash.nl. Filesharing is working fine as well:

How amazing is this?! We are using Pi-hole with Microsoft Active Directory infrastructure and that means that we can now benefit from the protection of Pi-hole on enterprise level :). Of course this test is limited but imagine the possibilities. You can now provide all your endusers with a ad-free and tracking free internet experience but still be in control if some specific website needs to be unblocked.

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Exchange Server / NetScaler

Create a backup Load Balancing Virtual Server using Citrix NetScaler

- by Vikash Jhagroe - 2 Comments.

Reading Time: 5 minutesCitrix NetScaler is very powerful in Load Balancing. In fact Citrix is one of the market leaders in providing flexible and very robust Load Balancing features using NetScaler. To load balance your resources, you have to configure Load Balancing and then create load balancing virtual servers. So that will protect you against a single backend server failure.

But what if you don’t want to balance the load between several backend server, but you only want a certain backend server go active for your end users as a backup in case the primary goes down? And because we have a small setup, we only have one NetScaler running. So no clustering, of high availability whatsoever.

In this post I will show you how you can configure a backup virtual load balancing server for existing load balancing virtual server.

Requirements for the configuration:

  • Citrix NetScaler 11.1 (www.citrix.com).
  • Primary resource (in my case a website).
  • Backup resource (in my case a website).
  • Ip addresses for the virtual servers.

My homelab setup
I am running this whole setup from my Microsoft Hyper-V 2016 server. Also I have deployed two Linux webservers, all very basic.

So let’s start.

The screenshots below show the actual IP address of webservers running a simple .html page. One is the primary webserver, and the other one I want to become active when the primary goes down.

 

Set up the Primary Load Balancing Virtual Server

So each website will have it’s own load balancing virtual server. In this way I can define the backup virtual server. I already added both webservers as a Server object.

I also created the HTTP service I want to load balance.

Navigate to Traffic Management -> Load Balancing -> Virtual Servers and click on Add.

Enter the setting for your primary load balancing virtual server. This is the load balancing virtual server where everyone will connect too. This is the one we will configure with the backup load balancing virtual server later on. Enter the required information and click on OK.

Now add your backend resources to this load balancing virtual server. Remember that is load balancing virtual server is primary, so your primary backend servers will have to be added here. Click on No Load Balancing Virtual Server Service Binding.

Click on the Select Service option to select the service we want to bind. Then click on Bind.

Click on Continue.

Click on Done.

Check the status of the load balancing virtual server. It should say UP.

Now it is time to test. When we browse to the IP address of this load balancing virtual server (192.168.1.33), we should see the webserver I want to be primary.

Set up the Secondary Load Balancing Virtual Server

This second load balancing virtual server will be the backup of the primary one. We will set this one up to connect to my secondary webserver.

Navigate to Traffic Management -> Load Balancing -> Virtual Servers and click on Add to create a new load balancing virtual server. Then enter the correct settings and click on OK.

Click on No Load Balancing to add the second webserver as a resource for this load balancing virtual server.

Make sure you select your backup resources here. I selected my secondary web server / website. Then click on Bind.

Click on Continue.

Click then on Done.

So now you should have two load balancing virtual server with status UP.

Check the secondary load balancing virtual server for connectivity to the second web server.

Set the backup Load Balancing Virtual Server

We have to edit the properties of the primary load balancing virtual server. Using the Protection option we are going to tell it to redirect traffic to the secondary load balancing virtual server, in case it’s own back end server goes down.

Open the properties of the primary load balancing virtual server and click on Protection.

Select the load balancing virtual server you want to use as a backup. In my case I select the load balance virtual server which is redirecting me to my second web server. Then click on OK.

Check if everything is set up correctly and then click on Done.

Do some testing

It’s time to test if the setup works like we want it. I am turning of the primary web server now.

And when I browse to my primary load balancing virtual server now, I am presented with the second web server! A job well-done.

We can see in the log of the NetScaler that it detected the primary web server is down.

This concludes this tutorial. Feel free to contact me of you have any questions or comments.

You can also follow me on twitter or add the rss feed from the blog and you will be notified when I add new posts.

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