Category Archives: Active Directory

Free module to manage Group Policy Preferences with PowerShell

I’ve used Group Policy Preferences since it had been Policy Maker. I’ve always used it through the GUI but a couple of months ago I thought: Why don’t we use PowerShell for this?
Apparently, the answer is “because there is no cmdlets available”. Yes, there is Group Policy Automation Engine, but it is a paid close-source product. The built-in GroupPolicy module just does not have cmdlets for GP Preferences (only one section is covered by it – Registry).

All that lead me to starting an open-source project to PowerShellize GPP: https://github.com/exchange12rocks/PSGPPreferences
The module is at a beginning stage, but you can already install it through the Gallery: https://www.powershellgallery.com/packages/PSGPPreferences/

Currently the module allows you only to create / delete / manage groups (not even users), but I hope to add other sections relatively fast, since the foundation has been implemented.
Right now the most difficult, but crucial task is writing tests – w/o tests regressions are quite likely. That’s why it is next in the roadmap.

Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 4 — AGPM

Previous part — Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 3 — Management Infrastructure

Introduction

When we talk about control version systems (CVS), the first thing comes to mind is, of course, program code. In the modern world, one cannot be a decent software developer if they do not use Git or TFS or Mercurial or Subversion etc. But this does not mean only developers benefit from the concept of CVS: Adobe provides designers with its own solutions to manage file versions.
What about us, IT administrators? Given the growing popularity of the infrastructure-as-a-code concept, many IT administrators have already adopted some kind of CVS to store scripts and configurations files.

Today I want to talk about version control for group policies. You probably know that group policies are not exactly text files, therefore, traditional CVSes are not the best choice here. That’s why Microsoft came up with its own solution, which allows us to track changes, compare GPO versions and quickly restore the previous ones: Advanced Group Policy Management (AGPM).

Interesting, that it is not just a CVS, but is also a tool to delegate group policies administration with built-in approval management mechanism.
But even if you work in a small team and do not need GPO management delegation, I still encourage you to use AGPM as a version control system.

AGPM is a part of Microsoft Desktop Optimization Pack, which is a free software set available to Microsoft Software Assurance subscribers. Here’s the official documentation where you can learn more about the product.

Warning

AGPM is NOT a substitute for a proper Active Directory backup.


Continue reading Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 4 — AGPM

Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 3 — Management Infrastructure

Previous part — Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 2 — Post-Config

Introduction

Sorry it took me so long — a lot has happened in the last six months, including moving into another country and changing jobs. Also, as you can see from several previous posts, I got a little bit carried away with PowerShell.
Another thing with which I got carried away is this post: I even had to split it, eventually. That’s why today, I present you not one, but two blogs at once! Find the next one here: Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 4 — AGPM

Up to this point, we were working on our servers interactively, locally. This is considered not the best practice because you consume server resources to support an interactive logon session. Also it might be inconvenient when you manage a fleet of servers.
In this article we will setup remote management administrative stations, which we will use to manage servers in the lab from then on.


Continue reading Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 3 — Management Infrastructure

Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 2 — Post-Config

Previous part — Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 1 — Installation

Introduction

In this post we will perform two configurations on our Active Directory Domain Services instance: We’ll define security tiers which later become cornerstones of our privilege delegation principles and we’ll tune domain-joining parameters. Also a quick tweak for the DNS service.


Continue reading Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 2 — Post-Config

Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 1 — Installation

Introduction

Up to this day, Active Directory Domain Services (AD DS) has been the core of the Windows infrastructure. With each release of Windows Server, AD DS receives new features while keeping great backward compatibility. Windows Server 2016 brings following enhancements to AD DS:

In this blog we shall install the corner stone of our future infrastructure: a highly-available AD DS instance of two domain controllers. Our AD DS layout is going to be quite simple: two writable domain controllers in a single site.


Continue reading Building Highly-Available Windows Infrastructure: Command-line Style. AD DS. Part 1 — Installation

Huge refactoring of Synchronize-DNSZones.ps1

Today I finished huge refactoring of my Synchronize-DNSZones script (see more about it here). The main reason to refactor was to introduce a support to synchronize zone-level records. To efficiently achieve this, I converted a huge pile of code into several smaller functions. I also improved code readability by PS 3.0 standards (apparently, it is also StrictMode-compatible now).
I improved error handling by introducing 3 new error events:
55 – DNS-zone creation is not yet supported. (And I don’t think I’ll ever support it)
72 – Function New-DnsRecord failed.
82 – Cannot import DNSClient PowerShell module.

I finally replaces unapproved verbs in function names to approved ones (see Get-Verb). I shall change the name of the script itself later.
Fixed an issue when Receive-DnsData sometimes returns empty response and.
Fixed typos and incorrect error handling and slightly enhanced comments.
And I also added forgotten definition of $SMTPCc variable.

In the future I plan to add ShouldProcess support (WhatIf).

Pull-requests / issues are welcome!

LAPS presentation

Last December I was presenting at Moscow IT Pro UG about Microsoft LAPS. Finally, the record of the presentation is processed and available at YouTube:

Do not forget to enable English subtitles (they are NOT auto-translated :D)

You may find PPTX-file here.

After the presentation, I was asked a couple of questions:
Q: Does the GUI tool send the password in plain text over the network?
A: No, LDAP connection is encrypted with SASL. But if you are going to access the password attribute in your own scripts/tools, you may accidentally expose the password if you set LDAP_OPT_ENCRYPT = 0 or will use ldap_simple_bind w/o TLS/SSL.

Q: Why do we even need those local accounts? Why not to disable them completely?
A: In case a machine has lost its connection to AD (due to network configuration change, for example), you may want to bring it back on line w/o disruptive actions such as reboot, offline password reset etc. In case if you hope that the machine keeps your offline password hash, you may find yourself in a stressful situation, when you find out that it, in fact, does not.

Split-brain DNS Synchronizer

The latest version of the script available at GitHub.

Many companies use the same domain name for both internal and external servers hosting. When an internal domain name is a name of AD DS domain, and internal users must access some of the servers by their external IP-addresses, the problem arises: somehow all these external names must exist in the internal zone and the record information in these internal records must be in correspondence with the external ones. There are several possible solutions to resolve such situation:

1. Blindly forward all external requests to AD DS controllers. In this case, domain controllers are the primary name servers for the zone.

Pros:

  • Single point of management.
  • No new software on domain controllers required.

Cons:

  • You cannot point internal and external users to different hosts for the same DNS-record.
  • Requires to allow external users access to internal servers, which might be impossible due to security policies. Possible exposure of internal infrastructure to an external malicious user.
2. Have two separated set of DNS-servers for internal and external zones.

Pros:

  • You can point internal and external users to different hosts for the same DNS-record.
  • External users do not access internal servers.
  • No new software on domain controllers required.

Cons:

  • Two different points of management. DNS-records may become outdated.
3. Use DNS policies – the new Windows Server 2016 functionality.

https://blogs.technet.microsoft.com/teamdhcp/2015/08/31/split-brain-dns-in-active-directory-environment-using-dns-policies/

Pros:

  • Single point of management.
  • You can point internal and external users to different hosts for the same DNS-record.

Cons:

  • Requires domain controllers migration to the latest software, which is not possible for some organizations.
  • Requires to allow external users access to internal servers, which might be impossible due to security policies. Possible exposure of internal infrastructure to an external malicious user.

 

Currently, I prefer the second method, with two sets of DNS servers. But in that case we have another challenge: How to ensure that all DNS-records, which must point to the same location for both external and internal users, are in sync?
Continue reading Split-brain DNS Synchronizer