cisco wireless dynamic vlan assignment

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Dynamic VLAN Assignment: Wireless

Dynamic VLAN Assignment

Objective: To dynamically Assign Wireless User to VLAN based on user credentials. This type of setup is called “Dynamic VLAN Assignment”

Description:  Dynamic VLAN assignment is one such feature that places a wireless user into a specific VLAN based on the credentials supplied by the user. This task of assigning users to a specific VLAN is handled by a RADIUS authentication server, such as Cisco Secure ACS. This can be used, for example, to allow the wireless host to remain on the same VLAN as it moves within a campus network.

Related- Cisco ACS vs ISE Comparison

Therefore, when a client attempts to associate to a LAP registered with a controller, the LAP passes the credentials of the user to the RADIUS server for validation. Once the authentication is successful, the RADIUS server passes certain Internet Engineering Task Force (IETF) attributes to the user. These RADIUS attributes decide the VLAN ID that should be assigned to the wireless client. The SSID ( WLAN , in terms of WLC) of the client does not matter because the user is always assigned to this predetermined VLAN ID.

WLC Configuration

This configuration requires these steps:

Configure the WLC with the Details of the Authentication Server

• Configure the Dynamic Interfaces (VLANs)
• Configure the WLANs ( SSID )

It is necessary to configure the WLC so it can communicate with the RADIUS server to authenticate the clients, and also for any other transactions.

Complete these steps:

• From the controller GUI, click  Security .
• Enter the IP address of the RADIUS server and the Shared Secret key used between the RADIUS server and the WLC.

This Shared Secret key should be the same as the one configured in the RADIUS server under Network Configuration > AAA Clients > Add Entry. Here is an example window from the WLC:

Configure the Dynamic VLAN (Interfaces)

This procedure explains how to configure dynamic interfaces on the WLC. As explained earlier in this document, the VLAN ID specified under the Tunnel-Private-Group ID attribute of the RADIUS server must also exist in the WLC.

In the example, the user1 is specified with the  Tunnel-Private-Group ID of 10 (VLAN =10)  on the RADIUS server.

You can see the same dynamic interface (VLAN=10) configured in the WLC in this example. From the controller GUI, under the Controller > Interfaces window, the dynamic interface is configured.

• Click  Apply  on this window.

This takes you to the Edit window of this dynamic interface (VLAN 10 here).

Enter the IP Address and default Gateway of this dynamic interface

Note:  Because this document uses an internal DHCP server on the controller, the primary DHCP server field of this window points to the Management Interface of the WLC itself. You can also use an external DHCP server, a router, or the RADIUS server itself as a DHCP server to the wireless clients. In such cases, the primary DHCP server field points to the IP address of that device used as the DHCP server. Refer to your DHCP server documentation for more information.

• Click  Apply .

Now you are configured with a dynamic interface in your WLC. Similarly, you can configure several dynamic interfaces in your WLC. However, remember that the same VLAN ID must also exist in the RADIUS server for that particular VLAN to be assigned to the client.

Configure the WLANs (SSID)

This procedure explains how to configure the WLANs in the WLC.

• From the controller GUI, choose  WLANs > New  in order to create a new WLAN.

The New WLANs window is displayed.

• Enter the WLAN ID and WLAN SSID information.

You can enter any name to be the WLAN SSID. This example uses VLAN10 as the WLAN SSID.

• Click  Apply  in order to go to the Edit window of the WLAN SSID10.

Normally, in a wireless LAN controller, each WLAN is mapped to a specific VLAN (SSID) so that a particular user that belongs to that WLAN is put into the specific VLAN mapped. This mapping is normally done under the Interface Name field of the WLAN SSID window.

In the example provided, it is the job of the RADIUS server to assign a wireless client to a specific VLAN upon successful authentication. The WLANs need not be mapped to a specific dynamic interface on the WLC. Or, even though the WLAN to dynamic interface mapping is done on the WLC, the RADIUS server overrides this mapping and assigns the user that comes through that WLAN to the VLAN specified under the user  Tunnel-Group-Private-ID  field in the RADIUS server.

• Check the  Allow AAA Override  check box in order to override the WLC configurations by the RADIUS server.
• Enable the Allow AAA Override in the controller for each WLAN (SSID) configured.

When AAA Override is enabled, and a client has AAA and controller WLAN authentication parameters that conflict, client authentication is performed by the AAA (RADIUS) server. As part of this authentication, the operating system moves clients to a VLAN returned by the AAA server. This is predefined in the controller interface configuration.

For instance, if the corporate WLAN primarily uses a Management Interface assigned to VLAN 2, and if the AAA Override returns a redirect to VLAN 100, the operating system redirects all client transmissions to VLAN 100 even if the physical port to which VLAN 100 is assigned. When AAA Override is disabled, all client authentication defaults to the controller authentication parameter settings, and authentication is only performed by the AAA server if the controller WLAN does not contain any client-specific authentication parameters.

Continue Reading:

CONFIGURE INTERFACES ON WIRELESS CONTROLLER 5508

Wireless Interview Questions

ABOUT THE AUTHOR

I am here to share my knowledge and experience in the field of networking with the goal being – “The more you share, the more you learn.”

I am a biotechnologist by qualification and a Network Enthusiast by interest. I developed interest in networking being in the company of a passionate Network Professional, my husband.

I am a strong believer of the fact that “learning is a constant process of discovering yourself.” – Rashmi Bhardwaj (Author/Editor)

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What is Dynamic VLAN Assignment?

Written by Sean Blanton on May 24, 2021

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When it comes to the modern enterprise, few things are more important than network and identity security. With bad actors lurking around every corner (even inside of an organization itself), maintaining a strong, secure network along with keeping credentials safe is of utmost importance to the IT admin. Several network securing tools and techniques are being employed by IT admins today, especially during the global pandemic, but one that has been a foundational approach for many years is dynamic VLAN assignment. Since IT admins are dramatically stepping up the security of their IT environments, some are asking: what is dynamic VLAN assignment and how can it help secure the network?

Network Security with Dynamic VLAN Assignment

The simple answer is that dynamic VLAN assignment (or VLAN steering as it is sometimes called) is an excellent technique used to build on the underlying core strategy to control network access. VLAN assignments build on the use of RADIUS to control access to the network.

Via RADIUS integration, a WiFi access point (WAP) requires not only an SSID and passphrase, but a user’s unique set of credentials to access the network. Once a user has passed credentials through to the WAP to the RADIUS server and directory service, the RADIUS server will reply to the WAP that the user has been authenticated and inform what VLAN they are assigned to.

IT admins configure the system to identify which users and/or groups are assigned to which VLAN. Those VLANs can be set up on the WiFi network for any number of reasons including security and compliance. By segmenting users and authenticating them with their unique credentials, IT admins can increase security significantly. This approach helps separate out critical areas of the network, and can be especially helpful in compliance situations where, for example, the cardholder data environment (CDE) can be separated from the rest of the network making PCI Compliance far easier.

Challenges with Dynamic VLAN Assignments

The challenge with this approach is the overhead for IT admins. Traditionally, to implement dynamic VLAN assignments would require a great deal of infrastructure, configuration, and administration. For starters, IT organizations would need to set up their own FreeRADIUS server and connect that instance to the wireless access points and the identity provider (IdP), often, Microsoft ® Active Directory ® .

In many networks, the IT group would also need to configure endpoints with supplicants so that they could talk to the RADIUS server over the proper protocols. All of this ended up being a significant disincentive for IT admins, and that is why many WiFi networks are secured simply with an SSID and passphrase.

With the introduction of modern cloud RADIUS solutions, however, IT admins can virtually outsource the entire process for RADIUS authentication to WiFi and dynamic VLAN assignments. This Cloud RADIUS offering doesn’t focus on RADIUS only, but also acts as the identity management source of truth that can replace an on-prem Active Directory instance. It is available from the JumpCloud Directory Platform .

Cloud RADIUS and More

JumpCloud Directory Platform is everything a directory service was, and reimagines it for the cloud era. This includes endpoint management , identity and access management, single sign-on, multi-factor authentication, and network authentication tools such as Cloud RADIUS. Relatively new to the JumpCloud Suite is dynamic VLAN assignment functionality, so network administrators can better authorize their users’ access to crucial network resources. This feature just adds one more log to the bright flame of this cloud directory.

Interested in dynamic VLAN assignment and the rest of what the platform has to offer? Contact us , or check out our knowledge base to learn more.

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Sean Blanton is the Director of Content at JumpCloud and has spent the past decade in the wide world of security, networking and IT and Infosec administration. When not at work Sean enjoys spending time with his young kids and geeking out on table top games.

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