... too.The difference between a zone and a domain is important, but subtle. All top−level domains, and manydomains at the second level and lower, like berkeley.edu and hp.com, are broken into smaller, ... records, MB and MG. MB (mailbox) and MG (mail group) were to be DNS records specifying Internetmailboxes and mail groups (mailing lists) as subdomains of the appropriate domain. MB and MG never ... isn't delegated away, however, the zone contains the domain names and data inthe subdomain. So the bc.ca and sk.ca (British Columbia and Saskatchewan) subdomains of the ca domainmay exist, but might...