MX Access Policies (802.1X)
Overview
MX64/65(W), MX67/68(C/W/CW), MX75, Z3(C), and Z4(C) Teleworker Gateways, support port-based access policies using 802.1X. This feature can be leveraged for deployments where extra authentication is desired for devices that are connecting to the MX.
Use Cases
In the case of a teleworker device, these policies can be used to require authentication of devices before they are allowed to connect to a trusted VLAN that can access the corporate site-to-site VPN.
Access policies can also be used to provide an additional layer of security in remote sites where there is no staff to prevent users or employees from attempting to connect additional devices to the MX or Z.
Types of Access Policies
There are several different types of access policies that can be configured on an MX Security Appliance. It is important to understand the differences between these policies for appropriate configuration.
Open
An open-access policy does not require any authentication for a device connecting to the port.
802.1X
The 802.1X option authenticates connecting devices against the configured RADIUS servers by requiring credentials from the device.
Note: Packet captures taken from the MX will NOT show the EAP conversation between the MX and client. It will only show the traffic to and from the RADIUS server.
MAC Authentication Bypass
Configuring a port for the MAC authentication bypass access policy authenticates devices against the configured RADIUS servers using the MAC address of the device connected to the port. This access policy does not challenge devices for credentials.
MAC authentication bypass is an ideal choice for ports that have connecting devices that do not support 802.1X-based authentication.
WARNING: Prior to MX 16 firmware, MX/Z-Series appliances do not support the service type "call-check" attribute when sending MAB requests to the RADIUS server. Some servers, such as ISE, expect this value for MAB authentication.
In order for this to work on earlier firmware releases, configuration changes need be made on the RADIUS server to ignore this limitation.
Hybrid
The Hybrid authentication access policy leverages both the 802.1X and MAC authentication bypass authentication. A port configured for hybrid authentication will attempt to use 802.1X to authenticate the connected device to the configured RADIUS servers, but will failover to MAC authentication bypass if the connected device does not send any EAP traffic.
If attempts to authenticate a connected device using 802.1X and MAC authentication are unsuccessful, ports configured for hybrid authentication will continue to try to authenticate the device using both methods.
The device will be granted access if authentication is successful using either 802.1X or MAC authentication bypass.
Configuration
MX access policies are configured from the Security & SD-WAN > Configure > Addressing & VLANs page in dashboard.
Begin by ensuring that VLANs are enabled in the Routing section of the Addressing & VLANs page. This will reveal the Per-port VLAN Settings options, where we will configure our access policies.
To configure an access policy for a particular port, click on the port in the Per-port VLAN Settings table. Access policies can also be configured for multiple ports by selecting the desired ports using the check boxes and clicking the Edit button.
This will bring you to the Configure MX LAN ports menu. To configure the access policy:
- Set the Enabled option to enabled
- Set the Type to access
- Select the appropriate VLAN
- Choose the type of Access policy that should be used
- Click add radius server to configure at least one RADIUS server for authentication
- In the host field, specify the IP address used to reach the RADIUS server
- Specify the port the RADIUS server is available on
- Input the shared secret used by the RADIUS server in the secret field
Once the access policy has been configured for an MX LAN port, the Access Policy column of the Per-port VLAN Settings table will update accordingly.
Note: All the LAN ports on a MX or Z-Series device will use the same RADIUS server, even if the Access policies are different per-LAN port.
The 802.1X configurations on all Security Appliances are designed for a single-host authentication. Connecting multiple devices on the same port is not recommended.
MX and Z Source IP for RADIUS Authentication
Wireless-capable MX or Z-series devices have the option to authenticate wireless users with a RADIUS server. If this RADIUS server exists on the other side of a VPN tunnel, it will be important to note which IP address the MX/Z-series device will use when sending its Access-request messages. This article explains how to determine the source IP address used by a wireless-capable MX or Z-series device for RADIUS authentication.
The MX and Z-series devices use the Appliance LAN IP of the highest-numbered VLAN that is included in the VPN as the source address to reach the RADIUS server located on the other side of the VPN tunnel.
For MX/Z running MX19.1.6 and before, In situations where the MX is configured with Multiple VLANs, the NAS-IP will be the MX IP of the VLAN with the lowest VLAN ID. This is still the case even if that VLAN is not VPN-Enabled.
For all MX/Z running 19.1.6 and later, the NAS-IP will be the MX IP of the Highest-numbered VLAN ID.
In the example below, we have a remote MX configured with 2 VLANs 10 and 20, and an SSID named “PARIS” configured for “My RADIUS server” authentication. Please notice that the SSID's VLAN Assignment is set to default(10):
The following figure illustrates the SSID which has been configured to use VLAN 10 and Authentication type "My RADIUS server".
In Dashboard, under Security & SD-WAN/Teleworker Gateway > Configure > Wireless > SSID 1:
NPS server logs can be referenced to observe which IP the RADIUS request is sourced from. The following figure illustrates how the remote MX, in this case, is using 192.168.51.1 (VLAN 20 - Appliance LAN IP) as the source IP to reach the RADIUS server:
If the RADIUS server is across a VPN tunnel and the MX is in VPN Concentrator or Single LAN Routed/NAT mode, the MX will use a 6.X.X.X Address as the source address for the Access-Requests to the RADIUS Server.