Chapter 33. Authenticating a RHEL client to the network by using the 802.1X standard with a certificate stored on the file system

Procedure

1. Set the Extensible Authentication Protocol (EAP) to tls and the paths to the client certificate and key file:

   # nmcli connection modify enp1s0 802-1x.eap tls 802-1x.client-cert /etc/pki/tls/certs/client.crt 802-1x.private-key /etc/pki/tls/certs/certs/client.key

   Note that you must set the 802-1x.eap, 802-1x.client-cert, and 802-1x.private-key parameters in a single command.

2. Set the path to the CA certificate:

   # nmcli connection modify enp1s0 802-1x.ca-cert /etc/pki/tls/certs/ca.crt

3. Set the identity of the user used in the certificate:

   # nmcli connection modify enp1s0 802-1x.identity user@example.com

4. Optional: Store the password in the configuration:

   # nmcli connection modify enp1s0 802-1x.private-key-password password

   Important

   By default, NetworkManager stores the password in clear text in the connection profile on the disk, but the file is readable only by the root user. However, clear text passwords in a configuration file can be a security risk.

   To increase the security, set the 802-1x.password-flags parameter to 0x1. With this setting, on servers with the GNOME desktop environment or the nm-applet running, NetworkManager retrieves the password from these services. In other cases, NetworkManager prompts for the password.

5. Activate the connection profile:

   # nmcli connection up enp1s0

Procedure

1. Create a YAML file, for example ~/create-ethernet-profile.yml, with the following content:

   ---
   interfaces:
   - name: enp1s0
     type: ethernet
     state: up
     ipv4:
       enabled: true
       address:
       - ip: 192.0.2.1
         prefix-length: 24
       dhcp: false
     ipv6:
       enabled: true
       address:
       - ip: 2001:db8:1::1
         prefix-length: 64
       autoconf: false
       dhcp: false
     802.1x:
       ca-cert: /etc/pki/tls/certs/ca.crt
       client-cert: /etc/pki/tls/certs/client.crt
       eap-methods:
         - tls
       identity: client.example.org
       private-key: /etc/pki/tls/private/client.key
       private-key-password: password
   routes:
     config:
     - destination: 0.0.0.0/0
       next-hop-address: 192.0.2.254
       next-hop-interface: enp1s0
     - destination: ::/0
       next-hop-address: 2001:db8:1::fffe
       next-hop-interface: enp1s0
   dns-resolver:
     config:
       search:
       - example.com
       server:
       - 192.0.2.200
       - 2001:db8:1::ffbb

   These settings define an Ethernet connection profile for the enp1s0 device with the following settings:

   • A static IPv4 address - 192.0.2.1 with a /24 subnet mask
   • A static IPv6 address - 2001:db8:1::1 with a /64 subnet mask
   • An IPv4 default gateway - 192.0.2.254
   • An IPv6 default gateway - 2001:db8:1::fffe
   • An IPv4 DNS server - 192.0.2.200
   • An IPv6 DNS server - 2001:db8:1::ffbb
   • A DNS search domain - example.com
   • 802.1X network authentication using the TLS EAP protocol

2. Apply the settings to the system:

   # nmstatectl apply ~/create-ethernet-profile.yml

Procedure

1. Store your sensitive variables in an encrypted file:

   1. Create the vault:

      $ ansible-vault create vault.yml
      New Vault password: <vault_password>
      Confirm New Vault password: <vault_password>

   2. After the ansible-vault create command opens an editor, enter the sensitive data in the <key>: <value> format:

      pwd: <password>

   3. Save the changes, and close the editor. Ansible encrypts the data in the vault.

2. Create a playbook file, for example ~/playbook.yml, with the following content:

   ---
   - name: Configure an Ethernet connection with 802.1X authentication
     hosts: managed-node-01.example.com
     vars_files:
       - vault.yml
     tasks:
       - name: Copy client key for 802.1X authentication
         ansible.builtin.copy:
           src: "/srv/data/client.key"
           dest: "/etc/pki/tls/private/client.key"
           mode: 0600
   
       - name: Copy client certificate for 802.1X authentication
         ansible.builtin.copy:
           src: "/srv/data/client.crt"
           dest: "/etc/pki/tls/certs/client.crt"
   
       - name: Copy CA certificate for 802.1X authentication
         ansible.builtin.copy:
           src: "/srv/data/ca.crt"
           dest: "/etc/pki/ca-trust/source/anchors/ca.crt"
   
       - name: Ethernet connection profile with static IP address settings and 802.1X
         ansible.builtin.include_role:
           name: rhel-system-roles.network
         vars:
           network_connections:
             - name: enp1s0
               type: ethernet
               autoconnect: yes
               ip:
                 address:
                   - 192.0.2.1/24
                   - 2001:db8:1::1/64
                 gateway4: 192.0.2.254
                 gateway6: 2001:db8:1::fffe
                 dns:
                   - 192.0.2.200
                   - 2001:db8:1::ffbb
                 dns_search:
                   - example.com
               ieee802_1x:
                 identity: <user_name>
                 eap: tls
                 private_key: "/etc/pki/tls/private/client.key"
                 private_key_password: "{{ pwd }}"
                 client_cert: "/etc/pki/tls/certs/client.crt"
                 ca_cert: "/etc/pki/ca-trust/source/anchors/ca.crt"
                 domain_suffix_match: example.com
               state: up

   The settings specified in the example playbook include the following:

   ieee802_1x

   This variable contains the 802.1X-related settings.

   eap: tls

   Configures the profile to use the certificate-based TLS authentication method for the Extensible Authentication Protocol (EAP).

   For details about all variables used in the playbook, see the /usr/share/ansible/roles/rhel-system-roles.network/README.md file on the control node.

3. Validate the playbook syntax:

   $ ansible-playbook --ask-vault-pass --syntax-check ~/playbook.yml

   Note that this command only validates the syntax and does not protect against a wrong but valid configuration.

4. Run the playbook:

   $ ansible-playbook --ask-vault-pass ~/playbook.yml