Configure Cisco ASA VPN

This guide details how to configure Cisco ASA VPN to use the Okta RADIUS Server Agent.

Okta and Cisco ASA interoperate through RADIUS. For each Cisco ASA appliance, you can configure AAA Server groups, which can be RADIUS, TACAS+, LDAP, and so on. Using RADIUS, Okta's agent translates RADIUS authentication requests from the VPN into Okta API calls.

Before you begin

Meet the following network connectivity requirements before you install the Okta RADIUS agent:

Source Destination Port/Protocol Description
Okta RADIUS Agent Okta Identity Cloud TCP/443

HTTP

Configuration and authentication traffic.
Client Gateway Okta RADIUS Agent UDP/1812 RADIUS (Default, you can change this when you install and configure the RADIUS app) RADIUS traffic between the gateway (client) and the RADIUS agent (server).

Limitations

Enroll only a single Okta Verify device. Adding more Okta Verify devices can cause undefined or unexpected behavior.

If you've migrated a RADIUS-configured org from Classic Engine and you configure the Okta Verify authenticator with the number challenge, the challenge may be presented to RADIUS users even though it's not supported. To prevent this, enable the Early Access feature Disable number matching challenge for RADIUS. See Enable self-service features.

Supported factors

The size of the challenge message can be too large for the RADIUS prompt if you let users enroll too many authenticators. Okta recommends that you enroll no more than eight authenticators at a given time.

Okta supports the following authenticators for RADIUS apps:

MFA Authenticator

Password Authentication Protocol (PAP) Extensible Authentication Protocol - Generic Token Card (EAP-GTC) Extensible Authentication Protocol - Tunneled Transport Layer Security (EAP-TTLS)*
Duo (Push, SMS, and Passcode only) Supported Supported Duo passcode only.

Email

Supported

Supported

Supported when the string "EMAIL" is initially sent.
Refer to associated note.

RADIUS doesn't support inline enrollment with Email. When using inline enrollment, either disable Email or specify Password reset in Email settings.

Google authenticator

Supported Supported Supported, as long as challenge is avoided.
For example MFA only or "Password, passcode".

Okta Verify (TOTP and PUSH)

Supported (for one device only) Supported (for one device only) Supported (for one device only), as long as challenge is avoided.
For example:
MFA-only or "Password, MFA" for TOTP.
Push can work with primary authentication with MFA as the push challenge is sent out-of-band.

Okta Verify (number challenge)

Not supported

Not supported

Not supported

Phone (SMS and Voice call)

Supported Supported Supported when the string "CALL" is sent.
Refer to associated note.

YubiKey OTP

Supported Supported Supported - as long as challenge is avoided.
For example MFA only or "Password, passcode".

* RADIUS supports three authentication methods:

  • Password + MFA: Primary authentication using password, then the user is prompted to select factors to complete the authentication.
  • MFA Only: Instead of password, users enter either a one-time passcode (OTP), or one of EMAIL, SMS, CALL, PUSH (case insensitive).
  • Password and Passcode: Password entered immediately followed by a passcode in a request.
    Must be in the same request, for example: Abcd1234,879890" or "Abcd1234,SmS".

Protocols support the following authentication methods:

Protocol Supports
PAP Password and MFA, MFA, "Password and passcode".
EAP-TTLS MFA only, "Password and passcode".
EAP-GTC Password and MFA, MFA only, "Password and passcode".

Users must send the specified string EMAIL/SMS/CALL, which initially returns a failure. This results in the generation of an OTP provided using the specified method. The provided OTP can then be used for authentication.

EAP-TTLS doesn't support enrollment

Authentication will fail unexpectedly when EAP-TTLS is enabled, either Okta Verify or Phone are specified as the required enrollment policy, and the user isn't enrolled in that authenticator.

The U2F Security and Windows Hello MFA factors aren't compatible with RADIUS-enabled implementations. See Configuring RADIUS applications in Okta.

Passwordless authentication

RADIUS authentication uses passwords as the primary authentication mechanism. Traditional RADIUS authentication can't be performed with passwordless users. RADIUS can use other factors for authentication when the application setting property Okta performs primary authentication is cleared. See 2FA Only (Passwordless Mode) in RADIUS applications in Okta for addition detail.

For more information on passwordless authentication see Set up passwordless sign-in experience.

Typical workflow

Task

Description

Download the RADIUS agent

In the Admin Console, go to SettingsDownloads. Download the appropriate Okta RADIUS Agent for your environment.

For throughput, availability and other considerations, see Okta RADIUS Server Agent Deployment Best Practices.

Install Okta RADIUS server agent on Windows

Install Okta RADIUS server agent on Linux

Install the Okta RADIUS Server agent for your platform.

Add the Cisco VPN RADIUS app

Configure the app in your Okta org.

Configure the Cisco ASA gateway

Configure the gateway.

Configure optional settings

Configure optional settings, such as vendor specific attributes.

Test the Cisco RADIUS ASA VPN integration

Test the integration.

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