systemd-networkd-wait-online.service, systemd-networkd-wait-online — Wait for network to come online
systemd-networkd-wait-online is a one-shot system service that waits for the network to be configured. By default, it will wait for all links it is aware of and which are managed by systemd-networkd.service(8) to be fully configured or failed, and for at least one link to gain a carrier.
The following options are understood:
Network interface to wait for before deciding if the system is online. This is useful when a system has several interfaces which will be configured, but a particular one is necessary to access some network resources. This option may be used more than once to wait for multiple network interfaces.