Following this week's release of systemd 242, one of the newly-merged features for what will become systemd 243 is support for MACsec within the networkd code.

MACsec is the Media Access Control Security specification to better secure Ethernet traffic against "most" security threats. MACsec can fend off denial of service issues, Man-In-The-Middle attacks, passive wiretapping, and other attacks via this 802.1AE standard.

With this pull now merged into systemd Git, the networkd code supports MACsec. More details on the relevant tunables via this commit.