IPv6 supports DNS record types that are supported in the DNS name-to-address and address-to-name lookup processes. The DNS record types support IPv6 addresses. IPv6 also supports the reverse mapping of IPv6 addresses to DNS names.
A name server is used to track information associated with domain names. A name server can maintain a database of hostname-to-address mappings. Each name can map to one or more IPv4 addresses, IPv6 addresses, or both address types. In order to use this service to map domain names to IPv6 addresses, you must specify a name server and enable the DNS.
Cisco software maintains a cache of hostname-to-address mappings for use by the connect, telnet, and ping commands, related Telnet support operations, and many other commands that generate command output. This cache speeds the conversion of names to addresses.
Similar to IPv4, IPv6 uses a naming scheme that allows a network device to be identified by its location within a hierarchical name space that provides for domains. Domain names are joined with periods (.) as the delimiting characters. For example, Cisco is a commercial organization that is identified by a com domain name, so its domain name is cisco.com. A specific device in this domain, the FTP server, for example, is identified as ftp.cisco.com.
The following table lists the IPv6 DNS record types.
Table 1 |
IPv6 DNS Record Types |
Record Type |
Description |
Format |
AAAA |
Maps a hostname to an IPv6 address. (Equivalent to an A record in IPv4.) |
www.abc.test AAAA 3FFE:YYYY:C18:1::2 |
PTR |
Maps an IPv6 address to a hostname. (Equivalent to a pointer record [PTR] in IPv4.)
Note |
Cisco software supports resolution of PTR records for the IP6.INT domain. |
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2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.8.1.c.0.y.y.y.y.e.f.f.3.ip6.int PTR www.abc.test |