802.1X Interfaces

The IEEE 802.1X protocol provides a method of authenticating a client (called a supplicant) over wired media. It also provides access for individual MAC addresses on a switch (called the authenticator) after those MAC addresses have been authenticated by an authentication server, typically a RADIUS (Remote Authentication Dial In User Service, defined by RFC 2865) server.

A Cumulus Linux switch acts as an intermediary between the clients connected to the wired ports and the authentication server, which is reachable over the existing network. EAPOL (Extensible Authentication Protocol (EAP) over LAN — EtherType value of 0x888E, defined by RFC 3748) operates on top of the data link layer; the switch uses EAPOL to communicate with supplicants connected to the switch ports.

Cumulus Linux implements 802.1X through the Debian hostapd package, which has been modified to provide the PAE (port access entity).

Supported Features and Limitations

  • 802.1X is supported on Broadcom-based switches (except the Hurricane2 switch). The Tomahawk, Tomahawk2, and Trident3 switch must be running in nonatomic mode.
  • 802.1X is supported on physical interfaces only, such as swp1 or swp2s0 (bridged/access only and routed interfaces).
    • The interfaces cannot be part of a bond.
    • 802.1X is not supported on eth0.
  • You can configure 802.1X interfaces for bridges in both VLAN-aware mode and traditional mode using the following features:
    • Parking VLAN
    • Dynamic VLAN
    • MAB (MAC-based authentication bypass)
  • MAB, parking VLAN, and dynamic VLAN all require a bridge access port.
  • In traditional bridge mode, parking VLANs and dynamic VLANs both require the destination bridge to have a parking VLAN ID or dynamic VLAN ID tagged subinterface.
  • When you enable or disable 802.1X on ports, hostapd reloads; however, existing authorized sessions do not reset.
  • Changing the 802.1X interface, MAB, or parking VLAN settings do not reset existing authorized user ports. However, removing all 802.1X interfaces or changing any of the following RADIUS parameters restarts hostapd, which forces existing, authorized users to re-authenticate:
    • RADIUS server IP address, shared secret, authentication port or accounting port
    • Parking VLAN ID
    • MAB activation delay
    • EAP reauthentication period
  • You can configure up to three RADIUS servers (in case of failover). However, do not use a Cumulus Linux switch as the RADIUS server.
  • 802.1X on Cumulus Linux has been tested with only a few wpa_supplicant (Debian), Windows 10 and Windows 7 supplicants.
  • RADIUS authentication is supported with FreeRADIUS and Cisco ACS.
  • 802.1X supports simple login and password, PEAP/MSCHAPv2 (Win7) and EAP-TLS (Debian).
  • Mako template-based configurations are not supported.
  • Cumulus Linux supports Multi Domain Authentication (MDA), where 802.1X is extended to allow authorization of multiple devices (a data and a voice device) on a single port and assign different VLANs to the devices based on authorization.
    • MDA is enabled by default; however, you need to assign a tagged VLAN for voice devices (see Configure 802.1X Interfaces for a VLAN-aware Bridge).
    • A maximum of four authorized devices (MAB + EAPOL) per port are supported.
    • The 802.1X enabled port must be a trunk port to allow tagged voice traffic from a phone; you cannot enable 802.1X on an access port.
    • Only one untagged VLAN and one tagged VLAN is supported on the 802.1X enabled ports.
    • Multiple MAB (non voice) devices on a port are supported for VLAN-aware bridges only. Authorization of multiple MAB devices for different VLANs is not supported.

Configure the RADIUS Server

Before you configure any interfaces for 802.1X, configure the RADIUS server.

Do not use a Cumulus Linux switch as the RADIUS server.

To add a popular and freely available RADIUS server called FreeRADIUS on a Debian workstation, do the following:

root@radius:~# apt-get update
root@radius:~# apt-get install freeradius-utils freeradius-common

When installed and configured, the FreeRADIUS server can serve Cumulus Linux running hostapd as a RADIUS client.

For more information, see the FreeRADIUS documentation.

Configure 802.1X Interfaces

All the 802.1X interfaces share the same RADIUS server settings. Make sure you configure the RADIUS server before you configure the 802.1X interfaces. See Configure the RADIUS Server, above.

To configure an 802.1X interface, you need to set the following parameters, then enable 802.1X on the interface:

  • The RADIUS accounting port, which defaults to 1813.
  • The RADIUS Server IPv4 or IPv6 address, which has no default, but is required. You can also specify a VRF.
  • The RADIUS shared secret, which has no default, but is required.

Configure 802.1X Interfaces for a VLAN-aware Bridge

NCLU Commands

NCLU handles all the 802.1X interface configuration, updating hostapd and other components so you do not have to manually modify configuration files.

  1. Create a simple interface bridge configuration on the switch and add the switch ports that are members of the bridge. You can use glob syntax to add a range of interfaces. The MAB and parking VLAN configurations require interfaces to be bridge access ports. The VLAN-aware bridge must be named bridge and there can be only one VLAN-aware bridge on a switch.

    cumulus@switch:~$ net add bridge bridge ports swp1-4
    
  2. Add the 802.1X RADIUS server IP address and shared secret:

    cumulus@switch:~$ net add dot1x radius server-ip 127.0.0.1
    cumulus@switch:~$ net add dot1x radius shared-secret mysecret
    

    You can specify a VRF for outgoing RADIUS accounting and authorization packets. The following example specifies a VRF called blue:

    cumulus@switch:~$ net add dot1x radius server-ip 127.0.0.1 vrf blue
    cumulus@switch:~$ net add dot1x radius shared-secret mysecret
    
  3. Enable 802.1X on the interfaces, then review and commit the new configuration:

    cumulus@switch:~$ net add interface swp1-4 dot1x
    cumulus@switch:~$ net pending
    cumulus@switch:~$ net commit
    

    To assign a tagged VLAN for voice devices and assign different VLANs to the devices based on authorization, run these commands:

    cumulus@switch:~$ net add interface swp1-4 dot1x voice-enable
    cumulus@switch:~$ net add interface swp1-4 dot1x voice-enable vlan 200
    cumulus@switch:~$ net pending 
    cumulus@switch:~$ net commit
    

Linux Commands

  1. Edit the /etc/network/interfaces file to create a simple interface bridge configuration on the switch and add the switch ports that are members of the bridge. The MAB and parking VLAN configurations require interfaces to be bridge access ports. The VLAN-aware bridge must be named bridge and there can be only one VLAN-aware bridge on a switch. The following example shows that swp1 thru swp4 are members of the bridge.

    cumulus@switch:~$ sudo nano /etc/network/interfaces
    ...
    auto bridge
    iface bridge
    bridge-ports swp1 swp2 swp3 swp4
    bridge-vlan-aware yes
    ...
    
  2. Edit the /etc/hostapd.conf file to configure 802.1X settings. The example below sets:

    • The IP address of the 802.1X RADIUS server to 127.0.0.1 (auth_server_addr=127.0.0.1). You can specify a VRF for outgoing RADIUS accounting and authorization packets (for example, to specify a VRF called blue: auth_server_addr=127.0.0.1%blue).
    • The shared secret to mysecret (auth_server_shared_secret=mysecret).
    • 802.1X on swp1 thru swp4 (interfaces=swp1,swp2,swp3,swp4).

      cumulus@switch:~$ sudo nano /etc/hostapd.conf
      ...
      interfaces=swp1,swp2,swp3,swp4
      mab_interfaces=
      parking_vlan_interfaces=
      parking_vlan_id=
      mab_activation_delay=30
      eap_reauth_period=0
      eap_send_identity=0
      ctrl_interface=/var/run/hostapd
      nas_identifier=localhost
      auth_server_addr=127.0.0.1
      auth_server_port=1812
      auth_server_shared_secret=mysecret
      acct_server_addr=
      acct_server_port=1813
      acct_server_shared_secret=mysecret
      ...
      
  3. Enable then restart the hostapd service so that the configuration ersists between reboots:

    cumulus@switch:~$ sudo systemctl enable hostapd
    cumulus@switch:~$ sudo systemctl restart hostapd
    

Configure 802.1X Interfaces for a Traditional Mode Bridge

NCLU Commands

NCLU and hostapd might change traditional mode configurations on the bridge-ports line in the /etc/network/interface file by adding or deleting special 802.1X traditional mode bridge-ports configuration stanzas in /etc/network/interfaces.d/. The source configuration command in /etc/network/interfaces must include these special configuration filenames. It must include at least source /etc/network/interfaces.d/*.intf so that these files are sourced during an ifreload.

  1. Create uplink ports. The following example uses bonds:

    cumulus@switch:~$ net add bond bond1 bond slaves swp5-6
    cumulus@switch:~$ net add bond bond2 bond slaves swp7-8
    
  2. Create a traditional mode bridge configuration on the switch and add the switch ports that are members of the bridge. A traditional bridge cannot be named **** bridge as that name is reserved for the single VLAN-aware bridge on the switch. You can use glob syntax to add a range of interfaces.

    cumulus@switch:~$ net add bridge bridge1 ports swp1-4
    
  3. Create bridge associations with the parking VLAN ID and the dynamic VLAN IDs. In this example, 600 is used for the parking VLAN ID and 700 is used for the dynamic VLAN ID:

    cumulus@switch:~$ net add bridge br-vlan600 ports bond1.600
    cumulus@switch:~$ net add bridge br-vlan700 ports bond2.700
    
  4. Add the 802.1X RADIUS server IP address and shared secret:

    cumulus@switch:~$ net add dot1x radius server-ip 127.0.0.1
    cumulus@switch:~$ net add dot1x radius shared-secret mysecret
    

    You can specify a VRF for outgoing RADIUS accounting and authorization packets.The following example specifies a VRF called blue:

    cumulus@switch:~$ net add dot1x radius server-ip 127.0.0.1 vrf blue
    cumulus@switch:~$ net add dot1x radius shared-secret mysecret
    
  5. Enable 802.1X on the interfaces, then review and commit the new configuration:

    cumulus@switch:~$ net add interface swp1-2 dot1x
    cumulus@switch:~$ net pending
    cumulus@switch:~$ net commit
    

Linux Commands

  1. Edit the /etc/network/interfaces file to create uplink ports and create a traditional mode bridge configuration on the switch.

    a. Create uplink ports. The following example uses bonds:

    cumulus@switch:~$ sudo nano /etc/network/interfaces
    ...
    auto bond1
    iface bond1
       bond-slaves swp5 swp6
    auto bond2
    iface bond2
       bond-slaves swp7 swp8
    ...
    

    b. Create a traditional mode bridge configuration on the switch and add the switch ports that are members of the bridge. You must also create bridge associations with the parking VLAN ID and the dynamic VLAN IDs. In this example, 600 is used for the parking VLAN ID and 700 is used for the dynamic VLAN ID.

    A traditional bridge cannot be named **** bridge as that name is reserved for the single VLAN-aware bridge on the switch. You can use glob syntax to add a range of interfaces.

    cumulus@switch:~$ sudo nano /etc/network/interfaces
    ...
    auto bridge1
    iface bridge1
      bridge-ports swp1-swp4
      bridge-vlan-aware no
    
    auto br-vlan600
    iface br-vlan600
      bridge-ports bond1.600
      bridge-vlan-aware no
    
    auto br-vlan700
    iface br-vlan700
      bridge-ports bond1.700
      bridge-vlan-aware no
    
  2. Edit the /etc/hostapd.conf file to configure 802.1X settings. The example below sets:

    • The IP address of the 802.1X RADIUS server to 127.0.0.1 (auth_server_addr=127.0.0.1). You can specify a VRF for outgoing RADIUS accounting and authorization packets (for example, to specify a VRF called blue: auth_server_addr=127.0.0.1%blue).
    • The shared secret to mysecret (auth_server_shared_secret=mysecret).
    • 802.1X on swp1, swp2, swp3, and swp4 (interfaces=swp1,swp2,swp3,swp4).

      cumulus@switch:~$ sudo nano /etc/hostapd.conf
      ...
      interfaces=swp1,swp2,swp3,swp4
      mab_interfaces=
      parking_vlan_interfaces=
      parking_vlan_id=
      mab_activation_delay=30
      eap_reauth_period=0
      eap_send_identity=0
      ctrl_interface=/var/run/hostapd
      nas_identifier=localhost
      auth_server_addr=127.0.0.1
      auth_server_port=1812
      auth_server_shared_secret=mysecret
      acct_server_addr=
      acct_server_port=1813
      acct_server_shared_secret=testing123
      ...
      
  3. Enable then restart the hostapd service so that the configuration persists between reboots:

    cumulus@switch:~$ sudo systemctl enable hostapd
    cumulus@switch:~$ sudo systemctl restart hostapd
    

Configure the Linux Supplicants

A sample FreeRADIUS server configuration needs to contain the entriesfor users host1 and host2 on swp1 and swp2 for them to be placed in a VLAN.

host1 Cleartext-Password := "host1password"
host2 Cleartext-Password := "host2password"

After being configured, each supplicant needs the proper credentials:

user@host1:~# cat /etc/wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=2
ap_scan=0
network={
        key_mgmt=IEEE8021X
        eap=TTLS MD5
        identity="host1"
        anonymous_identity="host1"
        password="host1password"
        phase1="auth=MD5"
        eapol_flags=0
}
user@host2:~# cat /etc/wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=2
ap_scan=0
network={
        key_mgmt=IEEE8021X
        eap=TTLS MD5
        identity="host2"
        anonymous_identity="host2"
        password="host2password"
        phase1="auth=MD5"
        eapol_flags=0
  }

To test that a supplicant (client) can communicate with the Cumulus Linux Authenticator switch, run the following command from the supplicant:

root@host1:/home/cumulus# wpa_supplicant -c /etc/wpa_supplicant.conf -D wired -i swp1
Successfully initialized wpa_supplicant
swp1: Associated with 01:80:c2:00:00:03
swp1: CTRL-EVENT-EAP-STARTED EAP authentication started
swp1: CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=4
swp1: CTRL-EVENT-EAP-METHOD EAP vendor 0 method 4 (MD5) selected
swp1: CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully
swp1: CTRL-EVENT-CONNECTED - Connection to 01:80:c2:00:00:03 compl

Or from another supplicant:

root@host2:/home/cumulus# wpa_supplicant -c /etc/wpa_supplicant.conf -D wired -i swp1
Successfully initialized wpa_supplicant
swp1: Associated with 01:80:c2:00:00:03
swp1: CTRL-EVENT-EAP-STARTED EAP authentication started
swp1: CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=4
swp1: CTRL-EVENT-EAP-METHOD EAP vendor 0 method 4 (MD5) selected
swp1: CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully
swp1: CTRL-EVENT-CONNECTED - Connection to 01:80:c2:00:00:03 comp

Configure Accounting and Authentication Ports

You can configure the accounting and authentication ports in Cumulus Linux. The default values are 1813 for the accounting port and 1812 for the authentication port. You can also change the reauthentication period for Extensible Authentication Protocol (EAP). The period defaults to 0 (no re-authentication is performed by the switch).

To use different ports:

NCLU Commands

The following example commands change:

  • The authentication port to 2812
  • The accounting port to 2813
  • The reauthentication period for EAP to 86400

    cumulus@switch:~$ net add dot1x radius authentication-port 2812
    cumulus@switch:~$ net add dot1x radius accounting-port 2813
    cumulus@switch:~$ net add dot1x eap-reauth-period 86400
    cumulus@switch:~$ net pending
    cumulus@switch:~$ net commit
    

Linux Commands

Edit the /etc/hostapd.conf file to change the accounting and authentication ports.The example below sets:

  • The accounting port to 2813 (auth_server_port=2813)
  • The authentication port to 2812
  • The reauthentication period for EAP to 86400 (eap_reauth_period=86400)

    cumulus@switch:~$ sudo nano /etc/hostapd.conf
    ...
    eap_reauth_period=86400
    eap_send_identity=0
    ctrl_interface=/var/run/hostapd
    nas_identifier=localhost
    auth_server_addr=127.0.0.1
    auth_server_port=2812
    auth_server_shared_secret=mysecret
    acct_server_addr=
    acct_server_port=2813
    ...
    

Restart the hostapd service :

cumulus@switch:~$ sudo systemctl restart hostapd

Configure MAC Authentication Bypass

MAC authentication bypass (MAB) enables bridge ports to allow devices to bypass authentication based on their MAC address. This is useful for devices that do not support PAE, such as printers or phones. You can change the MAB activation delay from the default of 30 seconds, but the delay must be between 5 and 30 seconds. After the delay limit is reached, the port enters MAB mode.

MAB must be configured on both the RADIUS server and the RADIUS client (the Cumulus Linux switch).

When using a VLAN-aware bridge, the switch port must be part of bridge named bridge.

To configure MAB:

NCLU Commands

Enable a bridge port for MAB. The following example commands enable bridge port swp1 for MAB:

cumulus@switch:~$ net add interface swp1 dot1x mab
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

Linux Commands

Edit the /etc/hostapd.conf file to enable a bridge port for MAB. The following example enables bridge port swp1 for MAB.

cumulus@switch:~$ sudo nano hostapd.conf
...
mab_interfaces=swp1
parking_vlan_interfaces=
parking_vlan_id=
mab_activation_delay=20
...

Restart the hostapd service:

cumulus@switch:~$ sudo systemctl restart hostapd

Configure a Parking VLAN

If a non-authorized supplicant tries to communicate with the switch, you can route traffic from that device to a different VLAN and associate that VLAN with one of the switch ports to which the supplicant is attached.

For VLAN-aware bridges, the parking VLAN is assigned by manipulating the PVID of the switch port. For traditional mode bridges, Cumulus Linux identifies the bridge associated with the parking VLAN ID and moves the switch port into that bridge. If an appropriate bridge is not found for the move, the port remains in an unauthenticated state where no packets can be received or transmitted.

When using a VLAN-aware bridge, the switch port must be part of bridge named bridge.

NCLU Commands

Run the following commands:

cumulus@switch:~$ net add dot1x parking-vlan-id 777
cumulus@switch:~$ net add interface swp1 dot1x parking-vlan
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

If the authentication for swp1 fails, the port is moved to the parking VLAN:

cumulus@switch:~$ net show dot1x interface swp1 details

Interface  MAC Address        Attribute                     Value
---------  -----------------  ----------------------------  -----------------
swp1       00:02:00:00:00:08  Status Flags                  [PARKED_VLAN]
                              Username                      vlan60
                              Authentication Type           MD5
                              VLAN                          777
                              Session Time (seconds)        24772
                              EAPOL Frames RX               9
                              EAPOL Frames TX               12
                              EAPOL Start Frames RX         1
                              EAPOL Logoff Frames RX        0
                              EAPOL Response ID Frames RX   4
                              EAPOL Response Frames RX      8
                              EAPOL Request ID Frames TX    4
                              EAPOL Request Frames TX       8
                              EAPOL Invalid Frames RX       0
                              EAPOL Length Error Frames Rx  0
                              EAPOL Frame Version           2
                              EAPOL Auth Last Frame Source  00:02:00:00:00:08
                              EAPOL Auth Backend Responses  8
                              RADIUS Auth Session ID        C2FED91A39D8D605

The following output shows a parking VLAN association failure. A VLAN association failure only occurs with traditional mode bridges when there is no traditional bridge available with a parking VLAN ID-tagged subinterface (notice the [UNKNOWN_BR] status in the output):

cumulus@switch:~$ net show dot1x interface swp3 details

Interface  MAC Address        Attribute                     Value
---------  -----------------  ----------------------------  -------------------------
swp1       00:02:00:00:00:08  Status Flags                  [PARKED_VLAN][UNKNOWN_BR]
                              Username                      vlan60
                              Authentication Type           MD5
                              VLAN                          777
                              Session Time (seconds)        24599
                              EAPOL Frames RX               3
                              EAPOL Frames TX               3
                              EAPOL Start Frames RX         1
                              EAPOL Logoff Frames RX        0
                              EAPOL Response ID Frames RX   1
                              EAPOL Response Frames RX      2
                              EAPOL Request ID Frames TX    1
                              EAPOL Request Frames TX       2
                              EAPOL Invalid Frames RX       0
                              EAPOL Length Error Frames Rx  0
                              EAPOL Frame Version           2
                              EAPOL Auth Last Frame Source  00:02:00:00:00:08
                              EAPOL Auth Backend Responses  2
                              RADIUS Auth Session ID        C2FED91A39D8D605

Linux Commands

Edit the /etc/hostapd.conf file to add the parking VLAN ID and port. The following example adds the parking VLAN ID 777 (parking_vlan_id=777) and port swp1 (parking_vlan_interfaces=swp1)

cumulus@switch:~$ sudo nano hostapd.conf
...
parking_vlan_interfaces=swp1
parking_vlan_id=777
...

If the authentication for swp1 fails, the port is moved to the parking VLAN.

Configure Dynamic VLAN Assignments

A common requirement for campus networks is to assign dynamic VLANs to specific users in combination with IEEE 802.1x. After authenticating a supplicant, the user is assigned a VLAN based on the RADIUS configuration.

For VLAN-aware bridges, the dynamic VLAN is assigned by manipulating the PVID of the switch port. For traditional mode bridges, Cumulus Linux identifies the bridge associated with the dynamic VLAN ID and moves the switch port into that bridge. If an appropriate bridge is not found for the move, the port remains in an unauthenticated state where no packets can be received or transmitted.

To enable dynamic VLAN assignment globally, where VLAN attributes sent from the RADIUS server are applied to the bridge:

NCLU Commands

Run the following commands:

cumulus@switch:~$ net add dot1x dynamic-vlan
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

You can specify the require option in the command so that VLAN attributes are required. If VLAN attributes do not exist in the access response packet returned from the RADIUS server, the user is not authorized and has no connectivity. If the RADIUS server returns VLAN attributes but the user has an incorrect password, the user is placed in the parking VLAN (if you have configured parking VLAN).

cumulus@switch:~$ net add dot1x dynamic-vlan require
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

The following example shows a typical RADIUS configuration (shown for FreeRADIUS, not typically configured or run on the Cumulus Linux device) for a user with dynamic VLAN assignment:

# # VLAN 100 Client Configuration for Freeradius RADIUS Server.
# # This is not part of the CL configuration.
vlan100client Cleartext-Password := "client1password"
      Service-Type = Framed-User,
      Tunnel-Type = VLAN,
      Tunnel-Medium-Type = "IEEE-802",
      Tunnel-Private-Group-ID = 100

Verify the configuration (notice the [AUTHORIZED] status in the output):

cumulus@switch:~$ net show dot1x interface swp1 details

Interface  MAC Address        Attribute                     Value
---------  -----------------  ----------------------------  --------------------------
swp1       00:02:00:00:00:08  Status Flags                  [DYNAMIC_VLAN][AUTHORIZED]
                              Username                      host1
                              Authentication Type           MD5
                              VLAN                          888
                              Session Time (seconds)        799
                              EAPOL Frames RX               3
                              EAPOL Frames TX               3
                              EAPOL Start Frames RX         1
                              EAPOL Logoff Frames RX        0
                              EAPOL Response ID Frames RX   1
                              EAPOL Response Frames RX      2
                              EAPOL Request ID Frames TX    1
                              EAPOL Request Frames TX       2
                              EAPOL Invalid Frames RX       0
                              EAPOL Length Error Frames Rx  0
                              EAPOL Frame Version           2
                              EAPOL Auth Last Frame Source  00:02:00:00:00:08
                              EAPOL Auth Backend Responses  2
                              RADIUS Auth Session ID        939B1A53B624FC56
cumulus@switch:~$ net show dot1x interface summary

Interface  MAC Address        Username      State         Authentication Type  MAB  VLAN
---------  -----------------  ------------  ------------  -------------------  ---  ----
swp1       00:02:00:00:00:08  000200000008  AUTHORIZED    unknown              NO   888

The following output shows a dynamic VLAN association failure. VLAN association failure only occurs with traditional mode bridges when there is no traditional bridge available with a parking VLAN ID-tagged subinterface in it (notice the [UNKNOWN_BR] status in the output):

cumulus@switch:~$ net show dot1x interface swp1 details

Interface  MAC Address        Attribute                     Value
---------  -----------------  ----------------------------  --------------------------------------
swp1       00:02:00:00:00:08  Status Flags                  [DYNAMIC_VLAN][AUTHORIZED][UNKNOWN_BR]
                              Username                      host2
                              Authentication Type           MD5
                              VLAN                          888
                              Session Time (seconds)        11
                              EAPOL Frames RX               3
                              EAPOL Frames TX               3
                              EAPOL Start Frames RX         1
                              EAPOL Logoff Frames RX        0
                              EAPOL Response ID Frames RX   1
                              EAPOL Response Frames RX      2
                              EAPOL Request ID Frames TX    1
                              EAPOL Request Frames TX       2
                              EAPOL Invalid Frames RX       0
                              EAPOL Length Error Frames Rx  0
                              EAPOL Frame Version           2
                              EAPOL Auth Last Frame Source  00:02:00:00:00:08
                              EAPOL Auth Backend Responses  2
                              RADIUS Auth Session ID        BDF731EF2B765B78

Linux Commands

Edit the /etc/hostapd.conf file to add the following options:

  • dynamic_vlan=1 (Specify dynamic_vlan=2 if you want VLAN attributes to be required. If VLAN attributes do not exist in the access response packet returned from the RADIUS server, the user is not authorized and has no connectivity. If the RADIUS server returns VLAN attributes but the user has an incorrect password, the user is placed in the parking VLAN, if you have configured parking VLAN).
  • radius_das_port=
  • radius_das_time_window=300
  • radius_das_require_event_timestamp=1
  • radius_das_require_message_authenticator=1

Remove the eap_send_identity=0 option. For example:

cumulus@switch:~$ sudo nano /etc/hostapd.conf
eap_server=0
ieee8021x=1
driver=wired
dynamic_vlan=1
interfaces=swp1,swp2,swp3,swp4
mab_interfaces=
parking_vlan_interfaces=swp1
parking_vlan_id=777
mab_activation_delay=30
eap_reauth_period=0
ctrl_interface=/var/run/hostapd
nas_identifier=localhost
auth_server_addr=127.0.0.1
auth_server_port=1812
auth_server_shared_secret=mysecret
acct_server_addr=
acct_server_port=1813
acct_server_shared_secret=
radius_das_port=
radius_das_time_window=300
radius_das_require_event_timestamp=1
radius_das_require_message_authenticator=1

Restart the hostapd service :

cumulus@switch:~$ sudo systemctl restart hostapd

The following example shows a typical RADIUS configuration (shown for FreeRADIUS, not typically configured or run on the Cumulus Linux device) for a user with dynamic VLAN assignment:

# # VLAN 100 Client Configuration for Freeradius RADIUS Server.
# # This is not part of the CL configuration.
vlan100client Cleartext-Password := "client1password"
      Service-Type = Framed-User,
      Tunnel-Type = VLAN,
      Tunnel-Medium-Type = "IEEE-802",
      Tunnel-Private-Group-ID = 100

To disable dynamic VLAN assignment, where VLAN attributes sent from the RADIUS server are ignored and users are authenticated based on existing credentials:

NCLU Commands

Run the net del dot1x dynamic-vlan command:

cumulus@switch:~$ net del dot1x dynamic-vlan
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

Linux Commands

Edit the /etc/hostapd.conf file to remove the following options:

  • dynamic_vlan=1
  • radius_das_port=
  • radius_das_time_window=300
  • radius_das_require_event_timestamp=1
  • radius_das_require_message_authenticator=1

Add the eap_send_identity=0 option. The following example shows the options in the /etc/hostapd.conf file

cumulus@switch:~$ sudo nano /etc/hostapd.conf
eap_server=0
ieee8021x=1
driver=wired
interfaces=
mab_interfaces=
parking_vlan_interfaces=swp1
parking_vlan_id=777
mab_activation_delay=30
eap_reauth_period=0
eap_send_identity=0
ctrl_interface=/var/run/hostapd
nas_identifier=localhost
auth_server_addr=127.0.0.1
auth_server_port=1812
auth_server_shared_secret=mysecret
acct_server_addr=
acct_server_port=1813
acct_server_shared_secret=

Restart the hostapd service.

cumulus@switch:~$ sudo systemctl restart hostapd

Enabling or disabling dynamic VLAN assignment restarts hostapd, which forces existing, authorized users to re-authenticate.

Configure MAC Addresses per Port

You can specify the maximum number of authenticated MAC addresses allowed on a port.

NCLU Commands

Run the net add dot1x max-number-stations <value> command. You can specify any number between 0 and 255. The default value is 4.

cumulus@switch:~$ net add dot1x max-number-stations 10
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

Linux Commands

Edit the /etc/hostapd.conf file to add the max_number_stations= option. For example:

cumulus@switch:~$ sudo nano /etc/hostapd.conf
eap_server=0
ieee8021x=1
driver=wired
dynamic_vlan=1
max_number_stations=10
interfaces=swp1,swp2,swp3,swp4
mab_interfaces=
parking_vlan_interfaces=swp1
parking_vlan_id=777
mab_activation_delay=30
eap_reauth_period=0
ctrl_interface=/var/run/hostapd
nas_identifier=localhost
auth_server_addr=127.0.0.1
auth_server_port=1812
auth_server_shared_secret=mysecret
acct_server_addr=
acct_server_port=1813
acct_server_shared_secret=
radius_das_port=
radius_das_time_window=300
radius_das_require_event_timestamp=1
radius_das_require_message_authenticator=1

Restart the hostapd service :

cumulus@switch:~$ sudo systemctl restart hostapd

Configure EAP Requests from the Switch

Cumulus Linux provides the send-eap-request-id option, which you can use to trigger EAP packets to be sent from the host side of a connection. For example, this option is required in a configuration where a PC connected to a phone attempts to send EAP packets to the switch via the phone but the PC does not receive a response from the switch (the phone might not be ready to forward packets to the switch after a reboot). Because the switch does not receive EAP packets, it attempts to authorize the PC with MAB instead of waiting for the packets. In this case, the PC might be placed into a parking VLAN to isolate it. To remove the PC from the parking VLAN, the switch needs to send an EAP request to the PC to trigger EAP.

To configure the switch send an EAP request, run these commands:

cumulus@switch:~$ net add dot1x send-eap-request-id
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

Only run this command if MAB is configured on an interface.

The PC might attempt 802.1X authorization through the bridged connection in the back of the phone before the phone completes MAB authorization. In this case, 802.1X authorization fails.

The net del dot1x send-eap-request-id command disables this feature.

RADIUS Change of Authorization and Disconnect Requests

Extensions to the RADIUS protocol (RFC 5176) enable the Cumulus Linux switch to act as a Dynamic Authorization Server (DAS) by listening for Change of Authorization (CoA) requests from the RADIUS server (Dynamic Authorization Client (DAC)) and taking action when needed, such as bouncing a port or terminating a user session. The IEEE 802.1x server (hostapd) running on Cumulus Linux has been adapted to handle these additional, unsolicited RADIUS requests.

Configure DAS

To configure DAS, provide the UDP port (3799 is the default port), the IP address, and the secret key for the DAS client.

NCLU Commands

The following example commands set the UDP port to the default port, the IP address of the DAS client to 10.0.2.228, and the secret key to myclientsecret:

cumulus@switch:~$ net add dot1x radius das-port default
cumulus@switch:~$ net add dot1x radius das-client-ip 10.0.2.228 das-client-secret mysecret123
cumulus@switch:~$ net commit

You can specify a VRF so that incoming RADIUS disconnect and CoA commands are received and acknowledged on the correct interface when VRF is configured. The following example specifies VRF blue:

cumulus@switch:~$ net add dot1x radius das-port default
cumulus@switch:~$ net add dot1x radius das-client-ip 10.0.2.228 vrf blue das-client-secret mysecret123
cumulus@switch:~$ net commit

You can configure up to four DAS clients to be authorized to send CoA commands. For example:

cumulus@switch:~$ net add dot1x radius das-port default
cumulus@switch:~$ net add dot1x radius das-client-ip 10.20.250.53 das-client-secret mysecret1
cumulus@switch:~$ net add dot1x radius das-client-ip 10.0.1.7 das-client-secret mysecret2
cumulus@switch:~$ net add dot1x radius das-client-ip 10.20.250.99 das-client-secret mysecret3
cumulus@switch:~$ net add dot1x radius das-client-ip 10.10.0.0.2 das-client-secret mysecret4
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

To see DAS configuration information, run the net show configuration dot1x command. For example:

cumulus@switch:~$ net show configuration dot1x

dot1x
  mab-activation-delay 5
  eap-reauth-period 0
  parking-vlan-id 100
  dynamic-vlan

  radius
    accounting-port 1813
    das-client-ip 10.0.2.228 das-client-secret mysecret123
    authentication-port 1812
    das-port 3799

Linux Commands

Edit the /etc/hostapd.conf file to add the following options to configure the UDP port, the IP address and secret key for the DAS client:

  • radius_das_port
  • radius_das_client

The following example sets the UDP port to the default port, the IP address of the DAS client to 10.0.2.228, and the secret key to mysecret123:

cumulus@switch:~$ sudo nano /etc/hostapd.conf
...
radius_das_port=3799
radius_das_client=10.0.2.228 mysecret123

You can specify a VRF so that incoming RADIUS disconnect and CoA commands are received and acknowledged on the correct interface when VRF is configured. The following example specifies VRF blue:

cumulus@switch:~$ sudo nano /etc/hostapd.conf
...
radius_das_port=3799
radius_das_client=10.0.2.228%blue mysecret123

You can configure up to four DAS clients to be authorized to send CoA commands. For example:

cumulus@switch:~$ sudo nano /etc/hostapd.conf
...
radius_das_port=3799
radius_das_client=10.20.250.53 mysecret1 
radius_das_client=10.0.1.7 mysecret2
radius_das_client=10.20.250.99 mysecret3
radius_das_client=10.10.0.0.2 mysecret4

Restart the hostapd service:

cumulus@switch:~$ sudo systemctl restart hostapd

You can disable DAS in Cumulus Linux at any time by running the following commands:

NCLU Commands

cumulus@switch:~$ net del dot1x radius das-port
cumulus@switch:~$ net del dot1x radius das-client-ip
cumulus@switch:~$ net pending
cumulus@switch:~$ net commit

Linux Commands

Edit the /etc/hostapd.conf file to remove the following options:

  • radius_das_port
  • radius_das_client

Restart the hostapd service:

cumulus@switch:~$ sudo systemctl restart hostapd

Terminate a User Session

From the DAC, users can create a disconnect message using the radclient utility (included in the Debian freeradius-utils package) on the RADIUS server or other authorized client. A disconnect message is sent as an unsolicited RADIUS Disconnect-Request packet to the switch to terminate a user session and discard all associated session context. The Disconnect-Request packet is used when the RADIUS server wants to disconnect the user after the session has been accepted by the RADIUS Access-Accept packet.

This is an example of a disconnect message created using the radclient utility:

$ echo "Acct-Session-Id=D91FE8E51802097" > disconnect-packet.txt
$ ## OPTIONAL ## echo "User-Name=somebody" >> disconnect-packet.txt
$ echo "Message-Authenticator=1" >> disconnect-packet.txt
$ echo "Event-Timestamp=1532974019" >> disconnect-packet.txt
# now send the packet with the radclient utility (from freeradius-utils deb package)
$ cat disconnect-packet.txt | radclient -x 10.0.0.1:3799 disconnect myclientsecret

To prevent unauthorized servers from disconnecting users, the Disconnect-Request packet must include certain identification attributes (described below). For a session to be disconnected, all parameters must match their expected values at the switch. If the parameters do not match, the switch discards the Disconnect-Request packet and sends a Disconnect-NAK (negative acknowledgment message).

  • The Message-Authenticator attribute is required.
  • If the packet comes from a different source IP address than the one defined by das-client-ip, the session is not disconnected and the hostapd logs the debug message: DAS: Drop message from unknown client.
  • The Event-Timestamp attribute is required. If Event-Timestamp in the packet is outside the time window, a debug message is shown in the hostapd logs: DAS: Unacceptable Event-Timestamp (1532978602; local time 1532979367) in packet from 10.10.0.21:45263 - drop
  • If the Acct-Session-Id attribute is omitted, the User-Nameattribute is used to find the session. If the User-Name attribute is omitted, the Acct-Session-Id attribute is used. If both the User-Name and the Acct-Session-Id attributes are supplied, they must match the username provided by the supplicant with the Acct-Session-Id provided. If neither are given or there is no match, a Disconnect-NAK message is returned to the RADIUS server with Error-Cause "Session-Context-Not-Found" and the following debug message is shown in the log:

    RADIUS DAS: Acct-Session-Id match
    RADIUS DAS: No matches remaining after User-Name check
    hostapd_das_find_global_sta: checking ifname=swp2
    RADIUS DAS: No matches remaining after Acct-Session-Id check
    RADIUS DAS: No matching session found
    DAS: Session not found for request from 10.10.0.1:58385
    DAS: Reply to 10.10.0.1:58385
    

The following is an example of the Disconnect-Request packet received by the switch:

RADIUS Protocol
Code: Disconnect-Request (40)
Packet identifier: 0x4f (79)
Length: 53
Authenticator: c0e1fa75fdf594a1cfaf35151a43c6a7
Attribute Value Pairs
AVP: t=Acct-Session-Id(44) l=17 val=D91FE8E51802097
AVP: t=User-Name(1) l=10 val=somebody
AVP: t=Message-Authenticator(80) l=18 val=38cb3b6896623b4b7d32f116fa976cdc
AVP: t=Event-Timestamp(55) l=6 val=1532974019
AVP: t=NAS-IP-Address(4) l=6 val=10.0.0.1

Bounce a Port

You can create a CoA bounce-host-port message from the RADIUS server using the radclient utility (included in the Debian freeradius-utils package). The bounce port can cause a link flap on an authentication port, which triggers DHCP renegotiation from one or more hosts connected to the port.

The following is an example of a Cisco AVPair CoA bounce-host-port message sent from the radclient utility:

$ echo "Acct-Session-Id=D91FE8E51802097" > bounce-packet.txt
$ ## OPTIONAL ## echo "User-Name=somebody" >> bounce-packet.txt
$ echo "Message-Authenticator=1" >> bounce-packet.txt
$ echo "Event-Timestamp=1532974019" >> bounce-packet.txt
$ echo "cisco-avpair='subscriber:command=bounce-host-port' " >> bounce-packet.txt
$ cat bounce-packet.txt | radclient -x 10.0.0.1:3799 coa myclientsecret

The message received by the switch is:

RADIUS Protocol
Code: CoA-Request (43)
Packet identifier: 0x3a (58)
Length: 96
Authenticator: 6480d710802329269d5cae6a59bcfb59
Attribute Value Pairs
AVP: t=Acct-Session-Id(44) l=17 val=D91FE8E51802097
Type: 44
Length: 17
Acct-Session-Id: D91FE8E51802097
AVP: t=User-Name(1) l=10 val=somebody
Type: 1
Length: 10
User-Name: somebody
AVP: t=NAS-IP-Address(4) l=6 val=10.0.0.1
Type: 4
Length: 6
NAS-IP-Address: 10.0.0.1
AVP: t=Vendor-Specific(26) l=43 vnd=ciscoSystems(9)
Type: 26
Length: 43
Vendor ID: ciscoSystems (9)
VSA: t=Cisco-AVPair(1) l=37 val=subscriber:command=bounce-host-port
Type: 1
Length: 37
Cisco-AVPair: subscriber:command=bounce-host-port

Configure the NAS IP Address

You can send the NAS IPv4 or IPv6 address in access request and accounting packets. You can only configure one NAS IP address on the switch, which is used for all interface authorizations.

To configure the NAS IP address, run the following commands:

NCLU Commands

The following command example sets the NAS IP address to 10.0.0.1:

cumulus@switch:~$ net add dot1x radius nas-ip-address 10.0.0.1

Linux Commands

Edit the /etc/hostapd.conf file and configure the own_ip_addr setting with the NAS IP address:

cumulus@switch:~$ sudo nano /etc/hostapd.conf
...
interfaces=swp1,swp2,swp3,swp4
mab_interfaces=
parking_vlan_interfaces=
parking_vlan_id=
mab_activation_delay=30
eap_reauth_period=0
eap_send_identity=0
ctrl_interface=/var/run/hostapd
own_ip_addr=10.0.0.1

Enable, then restart the hostapd service so that the configuration persists between reboots:

cumulus@switch:~$ sudo systemctl enable hostapd
cumulus@switch:~$ sudo systemctl restart hostapd

To delete the NAS IP address, either run the NCLU net del dot1x radius nas-ip-address command or edit the /etc/hostapd.conf file.

Troubleshooting

To check connectivity between two supplicants, ping one host from the other:

root@host1:/home/cumulus# ping 198.150.0.2
PING 11.0.0.2 (11.0.0.2) 56(84) bytes of data.
64 bytes from 11.0.0.2: icmp_seq=1 ttl=64 time=0.604 ms
64 bytes from 11.0.0.2: icmp_seq=2 ttl=64 time=0.552 ms
^C
--- 11.0.0.2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.552/0.578/0

You can run net show dot1x with the following options for more data:

  • json prints the command output in JSON format.
  • macs displays MAC address information.
  • port-details shows counters from the IEEE8021-PAE-MIB for ports.
  • radius-details shows counters from the RADIUS-CLIENT MIB (RFC 2618) for ports.
  • status displays the status of the daemon.

To check to see which MAC addresses have been authorized by RADIUS:

cumulus@switch:~$ net show dot1x macs
Interface     Attribute   Value
-----------   -------------  -----------------
swp1          MAC Addresses  00:02:00:00:00:01
swp2          No Data
swp3          No Data
swp4          No Data

To check the port detail counters:

cumulus@switch:~$ net show dot1x port-details

Interface  Attribute                                  Value
-----------  ----------------------------------------     ---------
swp1        Mac Addresses                              00:02:00:00:00:01
            authMultiSessionId                         96703ADC82D77DF2
            connected_time                             182
            dot1xAuthEapolFramesRx                     3
            dot1xAuthEapolFramesTx                     3
            dot1xAuthEapolLogoffFramesRx               0
            dot1xAuthEapolReqFramesTx                  2
            dot1xAuthEapolReqIdFramesTx                1
            dot1xAuthEapolRespFramesRx                 2
            dot1xAuthEapolRespIdFramesRx               1
            dot1xAuthEapolStartFramesRx                1
            dot1xAuthInvalidEapolFramesRx              0
            dot1xAuthLastEapolFrameSource              00:02:00:00:00:01
            dot1xAuthLastEapolFrameVersion             2
            dot1xAuthPaeState                          5
            dot1xAuthQuietPeriod                       60
            dot1xAuthReAuthEnabled                     FALSE
            dot1xAuthReAuthPeriod                      0
            dot1xAuthServerTimeout                     30
            dot1xAuthSessionAuthenticMethod            1
            dot1xAuthSessionId                         1B50FE8939FD9F5E
            dot1xAuthSessionTerminateCause             999
            dot1xAuthSessionTime                       182
            dot1xAuthSessionUserName                   testing
            dot1xPaePortProtocolVersion                2
            last_eap_type_as                           4 (MD5)
            last_eap_type_sta                          4 (MD5)

To check RADIUS counters:

cumulus@switch:~$ net show dot1x radius-details swp1

Interface  Attribute                                   Value
-----------  ----------------------------------------    ---------
swp1       radiusAccClientRequests                      1
           radiusAccClientResponses                     1
           radiusAccClientServerPortNumber              1813
           radiusAccServerAddress                       127.0.0.1
           radiusAuthClientAccessAccepts                1
           radiusAuthClientAccessChallenges             1
           radiusAuthClientAccessRejects                0
           radiusAuthClientAccessRequests               0
           radiusAuthClientServerPortNumber             1812
           radiusAuthServerAddress                      127.0.0.1
           radiusAuthServerIndex                        1

...

You can also check logging with the journalctl command:

cumulus@switch:~$ sudo journalctl –f –u hostapd
Apr 19 22:17:11 switch hostapd[12462]: swp1: interface state UNINITIALIZED->ENABLED
Apr 19 22:17:11 switch hostapd[12462]: swp1: AP-ENABLED
Apr 19 22:17:11 switch hostapd[12462]: Reading rule file /etc/cumulus/acl/policy.d/00control_ps ...
Apr 19 22:17:11 switch hostapd[12462]: Processing rules in file /etc/cumulus/acl/policy.d/00...
Apr 19 22:17:12 switch hostapd[12462]: Reading rule file /etc/cumulus/acl/policy.d/100_dot1x...
Apr 19 22:17:12 switch hostapd[12462]: Processing rules in file /etc/cumulus/acl/policy.d/ ..
Apr 19 22:17:12 switch hostapd[12462]: Reading rule file /etc/cumulus/acl/policy.d/99control
Apr 19 22:17:12 switch hostapd[12462]: Processing rules in file /etc/cumulus/acl/policy.d/99
Apr 19 22:17:12 switch hostapd[12462]: Installing acl policy
Apr 19 22:17:12 switch hostapd[12462]: done. 

You can perform more advanced troubleshooting with the following commands.

To increase the debug level in hostapd, copy over the hostapd service file, then add -d, -dd or -ddd to the ExecStart line in the hostapd.service file:

cumulus@switch:~$ cp /lib/systemd/system/hostapd.service /etc/systemd/system/hostapd.service
cumulus@switch:~$ sudo nano /etc/systemd/system/hostapd.service
...
ExecStart=/usr/sbin/hostapd –ddd –c /etc/hostapd.conf
...

To watch debugs with journalctl as supplicants attempt to connect:

cumulus@switch:~$ sudo journalctl -n 1000  -u hostapd      # see the last 1000 lines of hostapd debug logging
cumulus@switch:~$ sudo journalctl -f -u hostapd            # continuous tail of the hostapd daemon debug logging

To check ACL rules in /etc/cumulus/acl/policy.d/100_dot1x_swpX.rules before and after a supplicant attempts to authenticate:

cumulus@switch:~$ sudo cl-acltool -L eb | grep swpXX
cumulus@switch:~$ sudo cl-netstat | grep swpXX           # look at interface counters

To check tc rules in /var/lib/hostapd/acl/tc_swpX.rules with:

cumulus@switch:~$ sudo tc -s filter show dev swpXX parent 1:
cumulus@switch:~$ sudo tc -s filter show dev swpXX parent ffff:

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