Basic operation

  • When the switch is configured with only the IP address of a DNS server available to the switch, 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.

  • When the switch is configured with both of the following:

    • The IP address of a DNS server available to the switch

    • The domain suffix of a domain available to the configured DNS serverthen:

    • A DNS-compatible command that includes the host name of a device in the same domain as the configured domain suffix can reach that device.

    • A DNS-compatible command that includes a fully qualified domain name can reach a device in any domain that is available to the configured DNS server.

Example:

Suppose the switch is configured with the domain suffix mygroup. Switch.net and the IP address for an accessible DNS server. If an operator wants to use the switch to ping a target host in this domain by using the DNS name "leader" (assigned by a DNS server to an IP address used in that domain), the operator can use either of the following commands:

Figure 62: Example: of using either a host name or a fully qualified domain name

In the proceeding Example:, if the DNS server's IP address is configured on the switch, but a domain suffix is either not configured or is configured for a different domain than the target host, the fully qualified domain name must be used.

Note that if the target host is in a domain other than the domain configured on the switch:

  • The host's domain must be reachable from the switch. This requires that the DNS server for the switch must be able to communicate with the DNS servers in the path to the domain in which the target host operates.

  • The fully qualified domain name must be used, and the domain suffix must correspond to the domain in which the target host operates, regardless of the domain suffix configured in the switch.

Example:

Suppose the switch is configured with the domain suffix mygroup. Switch.net and the IP address for an accessible DNS server in this same domain. This time, the operator wants to use the switch to trace the route to a host named "remote-01" in a different domain named common.group.net. Assuming this second domain is accessible to the DNS server already configured on the switch, a traceroute command using the target's fully qualified DNS name should succeed.

Figure 63: Example: using the fully qualified domain name for an accessible target in another domain