When setting up a scanner appliance, you are prompted for primary and secondary DNS server addresses, as well as a domain.
I always leave the domain field blank without any obvious consequences. Someone else in the organisation just set up a scanner, and did enter a domain in this field, again with no obvious consequences.
Does anyone know what this is actually used for?
From the Scanner Appliance User Guide:
6. Next are three optional network settings, used for informational purposes only. These Appliance settings are not used to access the internal network for scanning or the Qualys Cloud Platform for software updates. To skip these settings, press ENTER three times.
– When the LAN WINS1 prompt appears, enter the IP address for the primary WINS server, if any. Press ENTER to continue.
– When the LAN WINS2 prompt appears, enter the IP address for the secondary WINS server, if any. Press ENTER to continue.
– When the DOMAIN NAME prompt appears, enter the domain name for the DNS server (for example, mydomain.com). Press ENTER to continue.