Configuring External Authentication Servers for IAPs

You can configure an external RADIUS Remote Authentication Dial-In User Service. An Industry-standard network access protocol for remote authentication. It allows authentication, authorization, and accounting of remote users who want to access network resources.  server, TACACS Terminal Access Controller Access Control System. TACACS is a family of protocols that handles remote authentication and related services for network access control through a centralized server. , and LDAP Lightweight Directory Access Protocol. LDAP is a communication protocol that provides the ability to access and maintain distributed directory information services over a network. server for user authentication. You can configure guest network using External Captive Portal A captive portal is a web page that allows the users to authenticate and sign in before connecting to a public-access network. Captive portals are typically used by business centers, airports, hotel lobbies, coffee shops, and other venues that offer free Wi-Fi hotspots for the guest users. profile for external authentication.

To configure a server, complete the following procedure:

  1. In the WebUI, set the filter to a group containing at least one AP.

    The dashboard context for the group is displayed.

  2. Under Manage, click Devices > Access Points.

    A list of APs is displayed in the List view.

  3. Click the Config icon.

    The tabs to configure the APs are displayed.

  4. Click Show Advanced.
  5. Click the Security tab.

    The Security page is displayed.

  6. In the Authentication Server panel, click + to create a new server.
  7. Select any of the following server types and configure the parameters for your deployment scenario.

    Table 1: Authentication Server Configuration

    Type of Server

    Parameters

    RADIUS

    Name

    Name of the external RADIUS server.

    Radsec

    Set Radsec to Enabled to enable secure communication between the RADIUS server and IAP by creating a TLS Transport Layer Security. TLS is a cryptographic protocol that provides communication security over the Internet. TLS encrypts the segments of network connections above the Transport Layer by using asymmetric cryptography for key exchange, symmetric encryption for privacy, and message authentication codes for message integrity. tunnel between the IAP and the server. If Radsec is enabled, the following configuration options are displayed:

    IP Address/FQDN

    IP address or the FQDN Fully Qualified Domain Name. FQDN is a complete domain name that identifies a computer or host on the Internet. of the external RADIUS server.

    Radsec Port

    Communication port number for RadSec TLS connection. By default, the port number is set to 2083.

    Auth Port

    Authorization port number of the external RADIUS server. The default port number is 1812.

    Dynamic Authorization

    To allow the APs to process RFC Request For Comments. RFC is a commonly used format for the Internet standards documentss. 3576-compliant CoA Change of Authorization. The RADIUS CoA is used in the AAA service framework to allow dynamic modification of the authenticated, authorized, and active subscriber sessions. and disconnect messages from the RADIUS server, select this check box. Disconnect messages terminate the user session immediately, whereas the CoA messages modify session authorization attributes such as data filters. When you enable the Dynamic Authorization option, the AirGroup CoA Port field is displayed with the port number for sending Bonjour support CoA on a different port than on the standard CoA port. The default value is 5999.

    Radsec Keepalive Type

    Specifies the keepalive Signal sent at periodic intervals from one device to another to verify that the link between the two devices is working. If no reply is received, data will be sent by a different path until the link is restored. A keepalive can also be used to indicate that the connection should be preserved so that the receiving device does not consider it timed out and drop it. message type to keep the Radsec server connection alive. Select one of the following Radsec Keepalive type options based on the Radsec server capabilities and system load requirements:

    Keepalive is recommended in a network where a RadSec server is connected to a large number of RadSec clients for tracking and port access sessions. The Radsec server requires additional resources to process status-server and access-request messages when compared to keepalive messages. This is because status server and access-request messages are RADIUS protocol packets. However, keepalive packets are TCP control packets that does not require any additional resources.

    NOTE: The Radsec Keepalive Type option is available only when Radsec option is enabled.

    Accounting Port

    The accounting port number used for sending accounting records to the RADIUS server. The default port number is 1813.

    NAS IP Address

    Enter the IP address.

    Shared Key and Retype Key

    Shared key for communicating with the external RADIUS server.

    NAS Identifier

    Use this to configure strings for RADIUS attribute 32, NAS Identifier, to be sent with RADIUS requests to the RADIUS server.

    Timeout

    The timeout duration for one RADIUS request. The IAP retries sending the request several times (as configured in the Retry count) before the user is disconnected. For example, if the Timeout is 5 seconds, Retry counter is 3, user is disconnected after 20 seconds. The default value is 5 seconds.

    Retry Count

    The maximum number of authentication requests that can be sent to the server group by the IAP. You can specify a value within the range of 1–5. The default value is 3 requests.

    Dead Time (in mins)

    Specify a dead time for authentication server in minutes. When two or more authentication servers are configured on the IAP and a server is unavailable, the dead time configuration determines the duration for which the authentication server is available if the server is marked as unavailable.

    If Dynamic RADIUS Proxy (DRP) is enabled on the APs, configure the following parameters:

    Service Type Framed User

    Select any of the following check boxes to send the service type as Framed User in the access requests to the RADIUS server:

    Query Status of RADIUS Servers (RFC 5997)

    Select any of the following check boxes to detect the server status of the RADIUS server:

    • Authentication—Select this check box to ensure the IAP sends a status-server request to determine the actual state of the authentication server before marking the server as unavailable.
    • Accounting—Select this check box to ensure the IAP sends a status-server request to determine the actual state of the accounting server before marking the server as unavailable.

    LDAP

    Name

    Name of the LDAP server.

    IP Address

    IP address of the LDAP server.

    Auth Port

    Authorization port number of the LDAP server. The default port number is 389.

    Admin-Distinguished-Name

    A distinguished name for the admin user with read and search privileges across all the entries in the LDAP database (the admin user need not have write privileges, but the admin user must be able to search the database, and read attributes of other users in the database).

    Admin Password and Retype Admin Password

    Password for the admin user.

    Base-Distinguished-Name

    Distinguished name for the node that contains the entire user database.

    Filter

    The filter to apply when searching for a user in the LDAP database. The default filter string is (objectclass=*).

    Key Attribute

    The attribute to use as a key while searching for the LDAP server. For Active Directory Microsoft Active Directory. The directory server that stores information about a variety of things, such as organizations, sites, systems, users, shares, and other network objects or components. It also provides authentication and authorization mechanisms, and a framework within which related services can be deployed., the value is sAMAccountName.

    Timeout

    Timeout interval within a range of 1–30 seconds for one RADIUS request. The default value is 5.

    Retry Count

    The maximum number of authentication requests that can be sent to the server group. You can specify a value within the range of 1–5. The default value is 3.

    TACACS

    Name

    Name of the server.

    Shared Key and Retype Key

    The secret key to authenticate communication between the TACACS client and server.

    Auth Port

    The TCP IP port used by the server. The default port number is 49.

    Timeout

    A number between 1 and 30 seconds to indicate the timeout period for TACACS+ Terminal Access Controller Access Control System+. TACACS+ provides separate authentication, authorization, and accounting services. It is derived from, but not backward compatible with, TACACS.  requests. The default value is 20 seconds.

    IP Address

    IP address of the server.

    Retry Count

    The maximum number of authentication attempts to be allowed. The default value is 3.

    Dead Time (in mins)

    Specify a dead time for authentication server in minutes. When two or more authentication servers are configured on the AP and a server is unavailable, the dead time configuration determines the duration for which the authentication server is available if the server is marked as unavailable.

    Session Authorization

    Enable this option to allow the authorization of sessions.

    External Captive Portal—The external captive portal servers are used for authenticating guest users in a WLAN.

     

    Name

    Enter a name for the profile.

    Type

    Select any one of the following types of authentication:

    • Radius Authentication—Select this option to enable user authentication against a RADIUS server.
    • Authentication Text—Select this option to specify an authentication text. The specified text will be returned by the external server after a successful user authentication.

    IP or Hostname

    Enter the IP address or the host name of the external splash page server.

    URL

    Enter the URL Uniform Resource Locator. URL is a global address used for locating web resources on the Internet. of the external captive portal server.

    Port

    Enter the port number that is used for communicating with the external captive portal server.

    Use VC IP in Redirect URL

    Select this check box to send the IP address of the virtual controller in the redirection URL when external captive portal servers are used. This option is disabled by default.

    Use HTTPS

    Select this to enforce clients to use HTTPS Hypertext Transfer Protocol Secure. HTTPS is a variant of the HTTP that adds a layer of security on the data in transit through a secure socket layer or transport layer security protocol connection. to communicate with the captive portal server. This option is available only if RADIUS Authentication is selected.

    Captive Portal Failure

    This field allows you to configure Internet access for the guest users when the external captive portal server is not available. Select Deny Internet to prevent guest users from using the network, or Allow Internet to access the network.

    Server Offload

    Select the check box to enable the server offload feature. The server offload feature ensures that the non-browser client applications are not unnecessarily redirected to the external captive portal server, thereby reducing the load on the external captive portal server.

    Prevent Frame Overlay

    Select this check box to prevent the overlay of frames. When enabled, the frames display only those pages that are in the same domain as the main page.

    Automatic URL Allowlisting

    On enabling this for the external captive portal authentication, the URLs that are allowed for the unauthenticated users to access are automatically allowlisted.

    Auth Text

    If the External Authentication splash page is selected, specify the authentication text that is returned by the external server after successful authentication. This option is available only if Authentication Text is selected.

    Redirect URL

    Specify a redirect URL if you want to redirect the users to another URL.

    Dynamic Authorization Only

    Name

    Name of the server.

    IP Address/FQDN

    IP address of the server.

    AirGroup CoA Port

    A port number for sending Bonjour support CoA on a different port than on the standard CoA port. The default value is 5999.

    Shared Key and Retype Key

    A shared key for communicating with the external RADIUS server. Change of Authorization(CoA) is a subset of Dynamic Authorization include disconnecting messages.

  8. Click Save.

To assign the authentication server to a network profile, select the newly added server when configuring security settings for a wireless or wired network profile.

You can also add an external RADIUS server when configuring a WLAN SSID Service Set Identifier. SSID is a name given to a WLAN and is used by the client to access a WLAN network. profile.

To configure the IP MTU Maximum Transmission Unit. MTU is the largest size packet or frame specified in octets (eight-bit bytes) that can be sent in networks such as the Internet. for EAP Extensible Authentication Protocol. An authentication protocol for wireless networks that extends the methods used by the PPP, a protocol often used when connecting a computer to the Internet. EAP can support multiple authentication mechanisms, such as token cards, smart cards, certificates, one-time passwords, and public key encryption authentication.  fragmentation, specify the value in the EAP Fragmentation MTU text box. The AP receives the EAP packet with certificate from the client and fragments it into smaller EAP fragments based on the configured IP MTU.