July 31, 2025

Introduction to Microsoft Entra ID

Microsoft Entra ID, formerly known as Azure AD, is the control center for Microsoft 365 and beyond.

While this blog focuses only on Microsoft 365, we will be talking about that.

All other services, like Exchange Online, Teams, SharePoint Online, and Intune rely on it, communicating with it in the background.

If you want to allow a user to access Teams or their email, you need to use Entra ID to accomplish this.

Technically speaking, Microsoft Entra ID, in its essence, is an Identity Provider. Its power is based on identity.

Identity or “Who are you?”

While not diving into psychological or philosophical perspectives, identity, in simple words, is: "Who you are."

In everyday life, we need to prove who we are by using our ID documents. They are provided to us by Trusted Identity Providers.

By the way, no one would ask you to provide a "Trusted Identity Representation"; they will just say identification document, but the terminology is important for the story. 😀

For example:

  • When you are taking out a loan at the bank, with all the paperwork, you also need to prove who you are by providing a Government ID issued by the trusted identity provider, which in this case is your government.
  • Let's say you are going to listen to or watch the opera, whoever likes what. At the entrance, you need to provide a ticket that grants you access to enter and enjoy the show. The ticket is provided by a trusted identity provider, which in this case is some event agency from which you bought it or the box office in the opera building.

In the case of Microsoft 365, if you want to access your email or Teams, you need to prove your identity by using your account, provided by a trusted identity provider, which in this case is Microsoft Entra ID.

Alright, we just understood the main purpose of an identity provider, in this case, Entra ID, and that's to check the identity of the person who is accessing the Microsoft 365 environment.

Identity types or “What are you?”

It's worth noting that there are also other identities that will access the Microsoft 365 environment, and they are not for humans.

So here is the breakdown of Entra ID identity types:

Identity TypeAssigned ToReal-World Examples
User IdentityHuman users (internal & external)Employees, consultants, partners, vendors, customers
Device IdentityPhysical endpoints used by people/workflowsLaptops, mobile phones, desktops, IoT devices
Workload IdentitySoftware entities (non-human actors)Applications, APIs, virtual machines, background services, containers

For now, I won’t go deeper into what these other identities mean. We will definitely cover them in future posts, but it’s good for you to know that they exist.

IAM, “What’s that?”

As we said before, Entra ID is like a control center for Microsoft 365, and managing users, blocking, and allowing access is the daily job of an administrator.

There is a generally accepted name for this kind of administration, and it’s called “Identity and Access Management,” or “IAM” for short.

IAM has its building blocks, and they are processes that are crucial for managing identity and access. They are:

  • Authentication
  • Authorization
  • Auditing (Accounting)

Authentication or “Is that you?”

The process, which takes place when Entra ID checks your identity after you enter your username and password, is called Authentication.

Let’s start from the beginning.

In order to log in to Microsoft 365, an administrator first needs to create a user account in Entra and assign you an email address and a password.

These are called “Credentials.”

  • Email address: It is used to tell Entra ID which account (identity) you want to log in as.
  • Password: It is an authentication factor used to verify if you are the one who you claim to be with the email address.

This type of Authentication is called Single-Factor Authentication because you are using only one factor.

Below you can see the basic process of Authentication.

Firstly, you enter your email address into the prompt and choose "Next":

If the user account exists in Entra ID, you will be redirected to the next prompt to enter your password:

If the authentication is successful, you will be redirected to Outlook:

Now we can say you are authenticated in Entra ID. 🙂

Authorization or “What you can do?”

In simple words, to be authorized to do something is “what are you allowed to do?”

Let's get back to our analogy of the Opera from the beginning.

  • You are going to the Opera House.
  • At the entrance, you provide your ticket.
  • They take it, and after verifying that it is a valid ticket, they allow you to go in.
  • But the seats are numbered, and you are restricted to just go to your seat, which is defined on your ticket, and let's say, it's the cheapest one.
  • But, for some reason, you refuse and go to have a seat in the VIP space.
  • After a few warnings, they throw you out, and you won't listen to or watch the opera anymore. 😀

So the message from this story is that you can sit only in the seats meant for you, or we can say for your ticket.

And that's predefined by the "Trusted Identity Provider" of the Opera tickets, which is the entity from which you bought the tickets.

This is similar to how authorization works in Entra ID.

It's a process of granting an already authenticated entity (User, Device, or Workload) permission to access specific resources or perform certain actions within those resources.

This way, when you log in to Microsoft 365, you can't go and start creating new users or accessing email mailboxes from other colleagues, except if the admin explicitly grants you those permissions, or in other words, except if the admin explicitly authorizes you to do that.

Here is an example.

We are already authenticated and logged into Outlook.

Let's say I want to send an email from a different email address than mine:

You see that I got an error telling me I don't have permissions.

I'm not thrown out, like from the Opera, but if I do this several times, the security team would definitely log me out, thinking I'm doing something suspicious, which would be the same as throwing me out. 😀

Auditing (Accounting) or “What did you do?”

Auditing is keeping track of what an identity did in the system.

These tracks are stored in Audit Logs, and an administrator can always see specific logs related to a specific account.

In the previous example for authorization, we mentioned that the security team would definitely log me off if they detected that I’m doing something potentially malicious, like trying to send an email from other employees' email addresses.

They detected this with the help of audit logs.

Summary

Microsoft Entra ID serves as the backbone of identity and access management for Microsoft 365.

It ensures secure authentication, precise authorization, and thorough auditing, making it indispensable for administrators and users alike.

By understanding its core principles and processes, organizations can effectively manage access to their digital environments while maintaining security and compliance.

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