LDAP vs. Active Directory: Key Differences IT Should Know (2026)
Gregg DavisUpdated 9 min read
LDAP and Active Directory are two of the most confused terms in identity management. They are related, and people often use them interchangeably when they shouldn't.
In short, LDAP is a protocol, and Active Directory is a directory service that uses that protocol. One defines how applications talk to a directory. The other is a directory, with a lot more built on top.
The difference matters when you choose a directory, connect an application to it, secure it, or plan how accounts get created and removed. In this article, we'll explain what each one is, compare them side by side, and show how they work together in a typical Microsoft environment.
What Is LDAP?
LDAP (Lightweight Directory Access Protocol) is an open, vendor-neutral protocol for reading and updating directory information. It gives applications a standard way to look up users, groups and devices in a directory, and to check a user's credentials against it.
LDAP grew out of work at the University of Michigan in the early 1990s as a lighter alternative to the X.500 directory protocols. The current version, LDAPv3, is defined by the IETF in RFC 4511 and its companion RFCs.
LDAP is not a product. It defines how a client talks to a directory, not where the data lives. Many directories on many platforms speak it, which is why so many applications support "LDAP authentication" out of the box.
How LDAP Organizes Data
An LDAP directory is a tree of entries. Each entry is an object, such as a user, a group or a computer, and it holds attributes like a name, an email address or a phone number.
Every entry has a distinguished name (DN) that describes its place in the tree. For example:
CN=Jane Doe,OU=Sales,DC=example,DC=com
Read from left to right, that's the common name Jane Doe, in the Sales organizational unit, in the example.com domain.
The schema defines which object classes exist (such as user or group) and which attributes each one can hold. Applications rely on these attribute names, so a mismatch between what an app expects and what the directory holds is a common cause of failed integrations.
Common LDAP Operations
LDAP defines a small set of operations that every compatible directory supports:
- Bind: Authenticate the connection, either anonymously, with a username and password (a simple bind), or through SASL mechanisms such as Kerberos.
- Search: Find entries that match a filter, such as every user in a given department.
- Compare: Check whether an entry has a given attribute value.
- Add, modify and delete: Create, change and remove entries.
- Unbind: Close the connection.
Search filters use a compact syntax. For example, (&(objectClass=user)(department=Sales)) finds every user object whose department is Sales. You'll see the same syntax in PowerShell's -LDAPFilter parameter and in the settings of most LDAP-enabled applications.
By default, LDAP runs on TCP port 389. LDAP over TLS (LDAPS) uses port 636, and a plain LDAP connection can also be upgraded to TLS with StartTLS.
What Is Active Directory?
Active Directory (AD) is Microsoft's directory service, first released with Windows 2000 Server. Its core role, Active Directory Domain Services (AD DS), stores users, groups, computers and policies, and it handles authentication and authorization across a Windows network.
AD uses LDAP as its main protocol for reading and writing directory data. Every domain controller is also an LDAP server, and the DNs, object classes and search filters described above all apply to it. That's why tools like ADSI Edit and ldp.exe can browse AD directly.
What Active Directory Adds Beyond LDAP
LDAP only describes how to access a directory. Active Directory adds everything needed to run an organization's identity on Windows:
- Kerberos authentication: Domain-joined computers and users sign in with Kerberos, not LDAP binds. LDAP is used mainly to look things up and to authenticate applications that don't speak Kerberos.
- Group Policy: Centralized settings for users and computers, such as password rules, drive mappings and security baselines. Our Active Directory Group Policy guide covers how it works.
- Domains, forests and trusts: A structure for dividing an organization into administrative boundaries and letting them trust each other.
- Multi-master replication: Domain controllers hold writable copies of the directory (read-only domain controllers aside) and replicate changes to each other.
- DNS integration: Clients find domain controllers through DNS service records, so AD and DNS are tightly linked.
Active Directory and Entra ID
Many organizations now run Active Directory alongside Microsoft Entra ID (formerly Azure AD), Microsoft's cloud identity service. In a hybrid setup, users are created in AD and synchronized to Entra ID, where they sign in to Microsoft 365 and cloud applications.
Entra ID is not LDAP-based. It uses modern web protocols such as OAuth 2.0, OpenID Connect and SAML. Applications that still need LDAP can use Microsoft Entra Domain Services, a managed domain that offers LDAP and Kerberos for legacy workloads.
LDAP vs. Active Directory: The Key Differences
Here's how the two compare at a glance:
| Aspect | LDAP | Active Directory |
|---|---|---|
| What it is | A protocol (a standard) | A directory service (a product) |
| Vendor | Open, vendor-neutral (IETF standard) | Microsoft |
| Scope | How clients access a directory | Stores identities, authenticates, applies policy |
| Authentication | Simple bind or SASL | Kerberos (primary), NTLM, LDAP binds |
| Platform | Cross-platform | Windows Server (Entra ID in the cloud) |
| Data structure | Defined by the directory's schema | Microsoft's AD schema, extensible |
| Extras | None, just directory access | Group Policy, replication, trusts, DNS |
| Typical clients | Linux servers, appliances, legacy apps | Windows PCs, servers, Microsoft 365 (via sync) |
The short version: you don't choose between LDAP and Active Directory. You choose a directory, and LDAP is one of the ways applications reach it.
How LDAP and Active Directory Work Together
LDAP and Active Directory operate at different layers. Active Directory is the directory, and LDAP is one of the languages used to talk to it. The real question is rarely "LDAP or AD?" It's "which directory do I run, and which protocols do my apps use to reach it?"
Typical LDAP Integrations With Active Directory
In most Microsoft environments, LDAP is how non-Windows systems connect to AD. Common examples include:
- Linux and Unix servers that look up users and groups in AD for sign-in and file permissions.
- VPNs, firewalls and Wi-Fi controllers that check a user's credentials and group membership before granting network access.
- Printers and multifunction devices that look up email addresses for scan-to-email.
- Older line-of-business applications that authenticate users with an LDAP bind instead of single sign-on.
Most of these integrations connect with a dedicated service account. Those bind accounts are easy to forget. They often have passwords that never expire and outlive the applications they were created for. Give each one an owner, review them in your regular Active Directory user account audits, and remove them when the application is retired.
Group membership is what makes these integrations useful. A VPN that allows members of a "VPN Users" group, or a Linux server that grants sudo to an "Admins" group, is only as accurate as those groups. Our guide to managing Active Directory groups effectively covers how to keep them clean.
Securing LDAP Traffic to Active Directory
A simple bind sends the user's password to the directory. Over plain LDAP on port 389, that password crosses the network unencrypted. Unsigned LDAP traffic can also be intercepted and replayed.
Newer domain controllers are stricter about this. On new Active Directory deployments, Windows Server 2025 requires LDAP signing by default and rejects simple binds over unencrypted connections. Microsoft recommends TLS (LDAPS) for simple binds and Kerberos for LDAP authentication. It also recommends LDAP channel binding, which ties an LDAPS session to its TLS connection.
Before you add Windows Server 2025 domain controllers, check older apps and devices that still use clear-text binds. Printers and appliances are the usual suspects. For the wider picture, see our Active Directory security best practices.
Other LDAP Directories
Because LDAP is an open standard, Active Directory isn't the only directory that speaks it. Common alternatives include:
- OpenLDAP: An open-source LDAP server, widely used on Linux.
- 389 Directory Server: The open-source LDAP server behind Red Hat Directory Server and FreeIPA.
- FreeIPA: An identity management system for Linux that combines LDAP, Kerberos and DNS, similar in spirit to Active Directory.
- Active Directory Lightweight Directory Services (AD LDS): Microsoft's LDAP-only directory, without domains, Group Policy or Kerberos sign-in. It's used by applications that need their own directory.
These make sense for Linux-centric environments or for applications that need a directory of their own. For organizations that run Windows and Microsoft 365, Active Directory and Entra ID remain the default. Our comparison of directory services tools looks at the options in more detail.
Why This Matters for Provisioning
Whichever directory you run, and whatever protocol your apps use to reach it, the hard part is keeping it accurate. Every user should have exactly the right access, and that access should change the moment their role or employment does.
That is the job of Active Directory user provisioning: reading changes from your HR system and writing the correct accounts, group memberships and licenses into AD and Entra ID automatically. When an employee leaves, disabling their AD account also cuts off every LDAP-connected system that checks it, from the VPN to the Linux servers. That only works if the account is disabled on time.
If you're moving identity to the cloud, our guide to migrating on-premises AD to Entra ID explains what changes for LDAP-dependent applications.
How ezOnboard Helps
ezOnboard keeps Active Directory accurate, so everything that relies on it over LDAP is accurate too. It connects your HR system to Active Directory, Entra ID and Exchange.
When HR records a hire, a transfer or a departure, ezOnboard creates, updates or disables the account automatically. It places users in the right OU, sets their directory attributes and adds or removes group memberships based on your rules.
Because the agent runs inside your network, it works with on-premises Active Directory directly, and your personnel data stays in your environment.
Book a demo to see it in action, or try the ROI calculator to estimate your savings.
Frequently Asked Questions
Is Active Directory the same as LDAP?
No. LDAP is a protocol for accessing a directory. Active Directory is a directory service that supports LDAP, along with Kerberos, Group Policy and other features.
Can you use LDAP without Active Directory?
Yes. LDAP is an open standard, and there are many LDAP-compatible directories, such as OpenLDAP and 389 Directory Server, that have nothing to do with Microsoft.
Does Entra ID use LDAP?
Not natively. Microsoft Entra ID uses modern protocols like OAuth 2.0, OpenID Connect and SAML. Applications that still require LDAP can use Microsoft Entra Domain Services, which provides a managed domain with LDAP support.
What ports do LDAP and LDAPS use?
LDAP uses TCP port 389 and LDAPS uses port 636. In Active Directory, the global catalog also answers LDAP queries on port 3268, or 3269 over TLS.
Is LDAP secure?
LDAP can be secure if the connection is encrypted and signed. Plain simple binds over port 389 send passwords in clear text. Use LDAPS or StartTLS, require LDAP signing, and prefer Kerberos where the application supports it.
Which should I use, LDAP or Active Directory?
It isn't either/or. You choose a directory, often Active Directory and Entra ID, and your applications use protocols like LDAP to authenticate against it.