I noticed that when I selected DNS and DHCP in the OES section of Yast,
I also get the DNS and DHCP server under Linux.

Are both required?

(like if you don't select OES, you can still pick DNS and DHCP for

Or is the OES DNS/DHCP part not the actual DNS/DHCP "server" (would
service/process be a better word)? And the DNS/DHCP under Linux is the
actual "server/service/process"?