DNS Operation
A name server handles client-issued queries to the DNS server for locally defined hosts within a particular
zone as follows:
•
An authoritative name server responds to DNS user queries for a domain name that is under its zone of
authority by using the permanent and cached entries in its own host table. If the query is for a domain
name that is under its zone of authority but for which it does not have any configuration information,
the authoritative name server replies that no such information exists.
•
A name server that is not configured as the authoritative name server responds to DNS user queries by
using information that it has cached from previously received query responses. If no router is configured
as the authoritative name server for a zone, queries to the DNS server for locally defined hosts receive
nonauthoritative responses.
Name servers answer DNS queries (forward incoming DNS queries or resolve internally generated DNS
queries) according to the forwarding and lookup parameters configured for the specific domain.
High Availability
Cisco NX-OS supports stateless restarts for the DNS client. After a reboot or supervisor switchover, Cisco
NX-OS applies the running configuration.
Prerequisites for DNS Clients
The DNS client has the following prerequisites:
•
You must have a DNS name server on your network.
Licensing Requirements for DNS Clients
The following table shows the licensing requirements for this feature:
Licence RquirementProduct
DNS requires no license. Any feature not included in a license package is bundled
with the Cisco NX-OS system images and is provided at no extra charge to you. For
a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS
Licensing Guide.
Cicco NX-OS
Default Settings for DNS Clients
The following table shows the default settings for DNS client parameters.
Cisco Nexus 3548 Switch NX-OS System Management Configuration Guide, Release 6.x
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Configuring DNS
DNS Operation
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