7.3. Configuring a MACsec connection by using nmstatectl

Procedure

1. On the first host on which you configure MACsec, create the connectivity association key (CAK) and connectivity-association key name (CKN) for the pre-shared key:

   1. Create a 16-byte hexadecimal CAK:

      # dd if=/dev/urandom count=16 bs=1 2> /dev/null | hexdump -e '1/2 "%04x"'
      50b71a8ef0bd5751ea76de6d6c98c03a

   2. Create a 32-byte hexadecimal CKN:

      # dd if=/dev/urandom count=32 bs=1 2> /dev/null | hexdump -e '1/2 "%04x"'
      f2b4297d39da7330910a74abc0449feb45b5c0b9fc23df1430e1898fcf1c4550

2. On both hosts that you want to connect over a MACsec connection, complete the following steps:

   1. Create a YAML file, for example create-macsec-connection.yml, with the following settings:

      ---
      routes:
        config:
        - destination: 0.0.0.0/0
          next-hop-interface: macsec0
          next-hop-address: 192.0.2.2
          table-id: 254
        - destination: 192.0.2.2/32
          next-hop-interface: macsec0
          next-hop-address: 0.0.0.0
          table-id: 254
      dns-resolver:
        config:
          search:
          - example.com
          server:
          - 192.0.2.200
          - 2001:db8:1::ffbb
      interfaces:
      - name: macsec0
        type: macsec
        state: up
        ipv4:
          enabled: true
          address:
          - ip: 192.0.2.1
            prefix-length: 32
        ipv6:
          enabled: true
          address:
          - ip: 2001:db8:1::1
            prefix-length: 64
        macsec:
          encrypt: true
          base-iface: enp0s1
          mka-cak: 50b71a8ef0bd5751ea76de6d6c98c03a
          mka-ckn: f2b4297d39da7330910a74abc0449feb45b5c0b9fc23df1430e1898fcf1c4550
          port: 0
          validation: strict
          send-sci: true

   2. Use the CAK and CKN generated in the previous step in the mka-cak and mka-ckn parameters. The values must be the same on every host in the MACsec-protected network.

   3. Optional: In the same YAML configuration file, you can also configure the following settings:

      • A static IPv4 address - 192.0.2.1 with the /32 subnet mask
      • A static IPv6 address - 2001:db8:1::1 with the /64 subnet mask
      • An IPv4 default gateway - 192.0.2.2
      • An IPv4 DNS server - 192.0.2.200
      • An IPv6 DNS server - 2001:db8:1::ffbb
      • A DNS search domain - example.com

3. Apply the settings to the system:

   # nmstatectl apply create-macsec-connection.yml

Verification

1. Display the current state in YAML format:

   # nmstatectl show macsec0

2. Verify that the traffic is encrypted:

   # tcpdump -nn -i enp0s1

3. Optional: Display the unencrypted traffic:

   # tcpdump -nn -i macsec0

4. Display MACsec statistics:

   # ip macsec show

5. Display individual counters for each type of protection: integrity-only (encrypt off) and encryption (encrypt on)

   # ip -s macsec show