In the past ( SLES11 ) it was easy to get networking started when using the "RESCUE" option in the install disk.

1. Boot Rescue disk.
2. Login as "root"
3. Type ( #dhcpcd eth0 ) and presto, the network was started.

The question now with SYSTEMD and SLES15 Rescue, what is the new simple one liner to get the DHCP client running on eth0 or whatever it get's called?