Category: Uncategorized

Selective password synchronization with AAD-Connect

In my previous post, I talked about the possibility of using Kerberos Constraint Delegation to avoid having passwords in AAD. However, sometime you want to have a few passwords in AAD-Domain Services to ensure that administrators can still login to the VM’s interactively (RDP) or users are able to use certain services that are not published with Kerberos or aren’t web services.

In this post we will look at editing the configuration of AAD-Connect to synchronize the passwords* of users that have an attribute in AD present so that some users (like administrators) will be able to login to VM’s joined to AAD-DS using their on-premises passwords.

* see note below

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ADFS behind Azure Traffic Manager

When you have ADFS hosted on Azure (as per my previous post), you might want to look at using Traffic Manager and then especially the probes and the endpoints..

So, this post is to help you to configure ADFS behind the Azure Traffic Manager and ensure proper failover on service unavailability.

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AAD-DS + KCD-PT + Federation (or how to avoid passwords on the cloud)

New (and only available within Azure) are the Azure Active Directory Domain Services. This service is based on Azure Active Directory and the data replicated into it. It provides Domain Services as a service to subscription administrators and can be very useful for many scenario’s where domain services are required, but security or management of domain controllers in the cloud is a concern.

In many documents, you will see that you need to replicate user password [hashes] into AAD to make it fully work.. but this post is about how you can avoid that using Kerberos Constraint Delegation with Protocol Transition….
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Redundant SRX Junos to Azure VPN with VNET Peering

Ever since playing with BGP I was looking for a way to make redundant tunnels. As the local internet provider here would only allow me a single IP address, I looked at the other side. What if we have two Azure regions that have a VPN tunnel to my SRX and between each other. Routing would be dealt with by BGP and thus, I should be able to connect to both VNET’s through each of the VPN tunnels.

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ADFS on Azure

Azure Active Directory and thus any relying party on that service (such as Office 365) has two different modes for (your) custom domains that are added to it. Managed and Federated. Managed means that the authentication happens against the Azure Active Directory. The password (-hashes) of the user accounts are in Azure AD and no connection to any (on-premises) Active Directory Domain is made.

Managed domains have the advantage that you don’t require any additional infrastructure, and setting up the identities for logging on to Office 365 for example, is fairly easy. However, it does not support any Single-Sign-On which most companies do want. That is why AAD also supports Federated domains, in this case the authentication for a user happens against the corporate (on-premises) Active Directory through a service called ADFS (Active Directory Federation Services). More information on federated versus managed can be found on the Kloud blog (https://blog.kloud.com.au/2013/06/05/office-365-to-federate-or-not-to-federate-that-is-the-question/)

In this article we are going to take a look at how the federation service can be hosted in Azure (and possibly also on-premises) and what the architectures might look like.

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ImmutableID – mS-DS-ConsistencyGuid – AADSync

Paul Williams talked in his blog about using another attribute from on-premises Ad’s to act as the ImmutableID for Azure Active Directory (http://blog.msresource.net/2014/03/10/windows-azure-active-directory-connector-part-3-immutable-id/)

While making a very detailed blog entry on why and which attribute to choose, there wasn’t a guide on how to make this work in AADSync.

So a recent project got me thinking about this. In this particular scenario there is already a forest (1 domain) using DirSync to replicate their users to AAD, and the requirement is to prepare for an AD migration, while also adding other users to the same AAD tenant. As usual, user objects might be duplicate between the two forests and we want to use the mS-DS-ConsistencyGuid attribute to be the immutableID.

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Pass the Hash

When you create a new forest or new domain, you use the Domain Admin credentials. Through the use of the “Administrator” account you can control each and every workstation and server. You can install Exchange, System Center products and much much more. But Microsoft is probably thinking twice now about the framework they have chosen wherein the Administrator is master of your infrastructure.

As the Administrator account is so powerful, it’s a sweet spot for hackers, the target to get. And that’s probably why many people rename the administrator account to Guest (and vice versa) or something else. Many others keep the Administrator name but change the password to a very long one including special characters, but even that seems futile, by the discovery of an advanced hacking technique called Pass The Hash.

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Azure Networking S2S + P2S

In a previous post we looked at the ability of creating a Site-2-Site connection from Checkpoint to Azure using a Dynamic Gateway. In this post, we look at client-dialup (VPN) into the Azure network and establish routing between all the sites involved.

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RDS Gateway through WAP

I’ve been trying to get RDS Gateway to work behind my WAP proxy server which is included in Windows Server 2012 R2 and v.Next version. While it is possible to implement ADFS based authentication based on the URL: http://technet.microsoft.com/en-us/library/dn765486.aspx

But what if we wanted to publish the simple RDS Gateway on our backend server for direct RDP access.. ?

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Geo-Clustering

Geo Clustering exists in many options, and dependent highly on the requirements and technical capability. This post is to discuss some options and things to consider before deploying any geo-cluster.

Data GEO- Redundancy

The first dependency in clustering is storage capability. Data from the workload in the cluster will be written to disk and that data needs to be available on both sites. Within Microsoft SQL AlwaysOn can replicate the data for the instances and ensure it is available on both sites. It is also possible to have the storage perform data mirroring.

When sending data from site A to site B, two options exist: Synchronous and A-Synchronous.

Synchronous: Data is written to BOTH sites before the application or server receives a successful write notification

A-Synchonous: Data is written to the primary site, the application or server receives the write, and THEN the data is written to the second site.

Within a synchronous architecture, there is very limited chance of data-loss upon a failure, as the application knows the data is written in two locations. With A-synchronous data loss can occur.

While synchronous looks most tempting, it requires fast connections between the storage / servers in order to reduce latency for every I/O write action. Therefore this is not always possible and a-synchronous is the only option left.

Storage mirroring or AlwaysOn data replication must be used to provide data geo-redundancy

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