My colleague Mike Parker has a great new series of posts up on securing Exchange Server 2016 with Azure AD. This option may seem counter-intuitive at a glance, but given that most organisations are on a trajectory from Exchange Server to Exchange Online, this configuration can consolidate access control for e-mail in a single location (for instance, over the duration of a migration or for long-term co-existence). It also means that Azure AD Conditional Access policies can be used for Exchange resources on and off-premises, which improves security while enabling mobility.
This configuration has two parts:
- Get most Exchange Server components to use OAuth 2.0. This is known as Hybrid Modern Authentication.
- Publish Outlook Web App (OWA) and the Exchange Control Panel (ECP) using the Azure AD Application Proxy.
The second step is necessary because these components are not currently supported for Hybrid Modern Authentication. The major pre-requisite for publishing an application with the Azure AD Application Proxy is that it should be authenticated with Kerberos and the Application Proxy Connector machine accounts need to be configured to use Constrained Delegation (KCD) for the OWA and ECP Service Principal Name (SPN). Mike’s article takes you through all of this step-by-step. My post deviates a bit from Mike’s guide to consider the idiosyncrasies of the Exchange Alternative Service Account Credential (ASA), which has underpinned Kerberos in Exchange Server since 2010 SP1. If you are familiar with configuring Kerberos, the ASA will almost certainly hold some surprises. Maybe even a fourth head.
Continue reading “Forget what you know about Kerberos before configuring Exchange Server to use Kerberos”
Last week, Microsoft released Windows Server 2012 R2 Preview. Some information about new features like the Web Application Proxy role began to emerge from recent industry events, but there isn’t an awful lot to absorb at the moment. Having played around with the preview for a few days, I’m pleased to report that the new features look good. While there are always niggles and unsupported scenarios, the features themselves are bringing Microsoft’s Identity and Access Management (IAM) offerings nearer to parity with the industry leaders. These changes should be of particular interest for SharePoint on-premises and Office 365 customers, as a number of scenarios that were on the bleeding edge of ADFS/UAG capabilities have been brought into the fold with some important enhancements to ADFS, which isn’t just for federation anymore.
In short, we get a new Claims-Aware Reverse Proxy, Device Claims in and outside of the network, Multiple-Factor Authentication and other enhancements for making access control decisions on more than just a username and password. I’ve discussed all of these topics routinely over the last couple of years in SharePoint on-premises and Office 365 contexts, but the current provisions in ADFS and UAG are not as elegant as what we find in the preview, so I’m keenly exploring the new functionality and will try to keep the content flowing. In this post I will focus on the features themselves, as there’s a lot of new stuff and the implementation of this functionality will only be clear with a bit more information than what you’ll find online today. I’m kind of rushing this out after limited use because I know there’s a big appetite for knowledge about the Microsoft Reverse Proxy roadmap, so apologies for the incompleteness in advance.
Continue reading “Significant Identity and Access Management Improvements in Windows Server 2012 R2”
Or… why it’s important to disable Host Time Synchronisation on a domain controller.
A few months ago I reminded myself of a major gotcha when planning a virtual infrastructure. Assume that you run more than one domain in more than one forest and that trusts are in place to authenticate users across those forests. This could be a development/test/staging environment, or as will no doubt be more common in the coming years, it could be a virtualised infrastructure. Continue reading “Windows Time, the PDC Emulator and the VM”