systemd Developer Vinay Kulkarni kulkarniv@vmware.com networkd.conf 5 networkd.conf networkd.conf.d Global Network configuration files /etc/systemd/networkd.conf /etc/systemd/networkd.conf.d/*.conf /usr/lib/systemd/networkd.conf.d/*.conf These configuration files control global network parameters. For e.g. DHCP Unique Identifier (DUID). This section configures the DHCP Unique Identifier (DUID) value used by DHCP protocol. DHCPv6 client protocol sends the DHCP Unique Identifier and the interface Identity Association Identifier (IAID) to a DHCP server when acquiring a dynamic IPv6 address. DHCPv4 client protocol sends IAID and DUID to the DHCP server when acquiring a dynamic IPv4 address if ClientIdentifier=duid. IAID and DUID allows a DHCP server to uniquely identify the machine and the interface requesting a DHCP IP. To configure IAID and ClientIdentifier, see systemd.network 5. The DUID value specified here overrides the DUID that systemd-networkd generates using the machine-id from the /etc/machine-id file. To configure DUID per-network, see systemd.network 5. The configured DHCP DUID should conform to the specification in RFC 3315, RFC 6355. To configure IAID, see systemd.network5 . The following options are available in [DUID] section: RawData= Specifies the DUID bytes as a single newline-terminated, hexadecimal string, with each byte separated by a ':'. systemd1, systemd.network5, machine-id1