1. Domain Name Resolution: provisioning guidance is in the networking chapter of the FAQ at this link:
http://www.openbsd.org/faq/faq6.html#Setup.resolver
2. su(1): exit the root shell to return to your normal user. You may find the doas(1) command and its configuration file doas.conf(5) to be an easier or more convenient way to become the superuser temporarily. The doas(1) command is mentioned in the afterboot(8) man page.