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DNS Resolver
DNS Resolver
The Domain Name System (DNS) resolver is designed for use in local network
domains where it enables use of a host name or fully qualified domain name
with DNS-compatible switch CLI commands.
DNS operation supports both IPv4 and IPv6 DNS resolution and multiple,
prioritized DNS servers. (For information on IPv6 DNS resolution, refer to the
latest IPv6 Configuration Guide for your switch.)
Terminology
Domain Suffix — Includes all labels to the right of the unique host name in
a fully qualified domain name assigned to an IP address. For example, in
the fully qualified domain name “device53.evergreen.trees.org”, the
domain suffix is “evergreen.trees.org”, while “device53” is the unique
(host) name assigned to a specific IP address.
Fully Qualified Domain Name — The sequence of labels in a domain name
identifying a specific host (host name) and the domain in which it exists.
For example, if a device with an IP address of 10.10.10.101 has a host name
of device53 and resides in the evergreen.trees.org domain, then the
device’s fully qualified domain name is device53.evergreen.trees.org and
the DNS resolution of this name is 10.10.10.101.
Host Name — The unique, leftmost label in a domain name assigned to a
specific IP address in a DNS server configuration. This enables the server to
distinguish a device using that IP address from other devices in the same
domain. For example, in the evergreen.trees.org domain, if an IPv4 address of
10.10.100.27 is assigned a host name of accounts015 and another IP address
of 10.10.100.33 is assigned a host name of sales021, then the switch configured
with the domain suffix evergreen.trees.org and a DNS server that resolves
addresses in that domain can use the host names to reach the devices with
DNS-compatible commands. For example:
ping accounts015
traceroute accounts015
Basic Operation
■ When the switch is configured with only the IP address of a DNS
server available to the switch, then a DNS-compatible command,
executed with a fully qualified domain name, can reach a device found
in any domain accessible through the configured DNS server.
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