For businesses, creating a secure network is of the utmost importance. This is why administrators may end up comparing multiple authentication standards and protocols, weighing out the pros and cons of each one. LDAP and RADIUS are prime examples of two common protocols in use today.

It can be easy to get confused about the differences and similarities between them, as there’s a bit of RADIUS-LDAP overlap. Let’s shed some light on these protocols by comparing and contrasting them so you understand which is more beneficial for your network.

What is LDAP?

Lightweight Directory Access Protocol, or LDAP, is a software protocol that enables an entity to look up data stored in a server. The “data” can be any information about organizations, devices, or users stored in directories. LDAP is the protocol used by servers to speak with on-premise directories.

Data is stored in a hierarchical structure called a Directory Information Tree (DIT), which organizes data into a branching “tree” structure, making it easier for admins to navigate their directories, find specific data, and administer user access policies.

Is LDAP an AAA Server?

In network security, AAA stands for authentication, authorization and accounting. This is a nickname often applied to RADIUS servers because they perform all the aforementioned functions.

An LDAP server can technically perform similar functions, so you could call a properly configured LDAP server by the same name. The problem with LDAP servers, however, is that they require on-premise hardware, sharply limiting their scalability. Additionally, LDAP is restricted to credential-based authentication, which isn’t exactly the most secure authentication method out there today. 

An AAA server is a crucial component to WPA2-Enterprise, also known as the 802.1X standard. AAA servers are specifically designed for network authentication, and LDAP servers on their own are not able to authenticate on Wi-Fi. Thus, while they are capable of performing many of the functions of AAA servers, they are inherently inferior to other options like RADIUS.

What is RADIUS?

The function of a RADIUS, or the Remote Access Dial-In User Service, is to authenticate the user and their device and authorize them for network access. The authorization process occurs each time a user re-connects to the network, and it takes the guesswork out of determining who is using your network.

Using a RADIUS is an effective way to boost network security and visibility. RADIUS can authenticate credentials, OTP, hardware security keys, and is especially effective when configured properly with certificates, which we will delve into in the next section. 

Differences Between RADIUS and LDAP

Radius LDAP Security Comparison

Both LDAP and RADIUS are authentication protocols that enable users to access their organization’s resources. It’s important to clarify that RADIUS and LDAP are not the same thing, and there are substantial differences in the way either one works.

For example, LDAP relies exclusively on unsecured credentials and with 10 million attacks targeting usernames and passwords occuring every day, it’s safe to say the usability and security flaws of credentials have accelerated. Not to mention many organizations are unsatisfied with credentials as authentication protection for their network due to IT help desk tickets and passwords sharing.

Another security vulnerability in LDAP and LDAP servers is they don’t necessarily have a way to protect users from accidentally connecting to the wrong server. Various cyber attacks prey on users by setting up false access points and encouraging people to connect to them. 

Using RADIUS allows for a key security mechanism to be employed: server certificate validation. This guarantees that the user only connects to the network they intend to by configuring their device to confirm the identity of the RADIUS by checking the server certificate. If the server certificate is not the one that the device is looking for, it will not send a certificate or credentials for authentication. This prevents users from falling victim to a variety of different network attacks, such as a Man-in-the-Middle attack.

One of the greatest security vulnerabilities of LDAP servers, however, is that they are generally on-premise. Not only does this make them costly to maintain, but it exposes them to a unique range of threats that cloud-hosted infrastructure doesn’t have to contend with. Such threats include power outages, severe weather, fire, and bad actors on-site. If you don’t house the LDAP server in a safe location, it’s possible that simple employee negligence could damage it, too.

It’s easy to see that RADIUS is superior to LDAP when it comes to network security. But how do they compare when it comes to authentication processes? 

RADIUS LDAP Authentication Comparison

Another one of LDAP’s greatest flaws is that it’s generally confined to credential-based authentication, as we touched on previously. It’s typically used to verify someone’s username and password, which are elements that can be easily stolen.

On the other hand, RADIUS is not limited to only one authentication method; RADIUS can use multiple factors of authentication (MFA) to provide greater protection than any one single method.

A RADIUS server can also be paired with a PKI, like SecureW2’s managed PKI, to authenticate digital certificates issued to end users. This makes RADIUS essential for Zero Trust Network Access (ZTNA), as you can ensure that each device on your network should have access. 

An important thing to note here is that, unlike LDAP servers, a RADIUS server does not store user and device information itself. It needs an Identity Provider (IDP) to function properly. IDPs are directories of user information that tell the RADIUS who an individual is and what type of access is warranted for them based on their role in an organization.

RADIUS LDAP Scalability Comparison

Another difference between LDAP and RADIUS stems from the use of on-premise servers. While historically both protocols relied on on-prem servers, RADIUS has evolved and can now be fully integrated into a cloud-based infrastructure. This is especially noteworthy due to the expenses associated with on-premise servers. These costs can be quite hefty, as they often demand at least some level of maintenance by a skilled professional, on-site security, and setup costs.

Furthermore, cloud environments offer stronger protection of data, easy access to authorized users, and greater control over who has data access They are also infinitely scalable as your organization grows. SecureW2 provides all the necessary tools to move your network to the cloud with our PKI and RADIUS services.


Put simply, RADIUS and LDAP are two authentication protocols. Although they have their differences, the truth is they aren’t mutually exclusive. It is certainly possible to use both at the same time.

While RADIUS-backed, certificate-based authentication does not require LDAP, they have often been combined to enable Identity Lookup. During the authentication process, Identity Lookup validates that a user is active within the organization by checking the identifying information against a user list. This solution is helpful, but cannot make the transition to a cloud-based network.

One common instance of RADIUS working with LDAP occurs when an organization uses a LDAP-compatible directory as their Identity Provider. Microsoft Active Directory is a popular example of an LDAP-backed directory that is often used as an IDP. Our own Cloud RADIUS can work in this scenario with our turnkey managed PKI to provide secure, certificate-based authentication to organizations using Active Directory.

The flaw with this setup, as we mentioned above, is that it relies upon on-premise hardware. If you’re looking to transition to a future-viable cloud environment, though, SecureW2 has a solution for you.

SecureW2 Solution For LDAP

At the end of the day, it’s important to acknowledge LDAP’s flaws. As a credential-based authentication protocol, it limits you to insecure (and frustrating) password use. On top of that, LDAP’s association with on-premise servers and equipment means it’s like an anchor to the past in a world that is quickly migrating to the cloud.

Luckily, SecureW2 is able to eliminate the need for LDAP entirely in the identity lookup process. We offer an industry-exclusive identity lookup for SAML-based cloud directories that is used in tandem with certificate-based authentication to deliver excellent network security without the need for LDAP. 

The entire process becomes far easier to manage and more efficient for both end users and IT personnel by allowing organizations to move away from an expensive, on-premise LDAP infrastructure without losing any functionality. 

In the coming years, LDAP is simply not going to be able to withstand the transition to cloud-based infrastructure. Protect your network with the best possible Cloud RADIUS-backed solution, Check out our solutions page to see how Cloud RADIUS can work for you, and if you need more convincing see how we help our customers in this case study.

Eytan Raphaely

Eytan Raphaely is a digital marketing professional with a true passion for writing things that he thinks are really funny, that other people think are mildly funny. Eytan is a graduate of University of Washington where he studied digital marketing. Eytan has diverse writing experience, including studios and marketing consulting companies, digital comedy media companies, and more.

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