Out-of-band DNS record
An out-of-band DNS record is a DNS name which has the notion of "connecting" to that DNS name using programs which look up the A or AAAA record, but the ultimate destination cannot be represented using an IPv4 or IPv6 address. Examples of out-of-band DNS records include Tor onion domains, and scope ID's of
ipv6-literal dot net as used in Microsoft Windows. Out-of-band DNS records, by definition, cannot be represented using a real authoritative or recursive DNS server on the Internet. However, Universal Relay's "programmatic DNS server" can still give off the illusion of having an out-of-band DNS record.