200-301 · Question #1501
What does a router do when it is configured with the default DNS lookup settings, and a URL is entered on the CLI?
The correct answer is D. It attempts to query a DNS server on the network.. When a router encounters an unrecognized command that resembles a URL or hostname, and DNS lookup is enabled, it attempts to resolve that hostname by querying a DNS server.
Question
Options
- AIt continuously attempts to resolve the URL until the command is cancelled.
- BIt initiates a ping request to the URL.
- CIt prompts the user to specify the desired IP address.
- DIt attempts to query a DNS server on the network.
How the community answered
(36 responses)- A3% (1)
- B3% (1)
- C6% (2)
- D89% (32)
Why each option
When a router encounters an unrecognized command that resembles a URL or hostname, and DNS lookup is enabled, it attempts to resolve that hostname by querying a DNS server.
The router attempts to resolve for a limited time and then times out; it does not continuously attempt resolution indefinitely until manually cancelled.
Initiating a ping request is a specific command (`ping`) and is not the default behavior when an unrecognized URL is simply typed into the CLI.
The router's default action is to attempt automatic DNS resolution; it does not prompt the user to manually specify an IP address for the given URL.
By default, Cisco routers have `ip domain-lookup` enabled. If a URL or hostname is entered as an unrecognized command on the CLI, the router will attempt to resolve it by sending DNS queries to any configured DNS servers on the network.
Concept tested: Router DNS lookup behavior
Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dns/configuration/15-mt/dns-15-mt-book/dns-cfg-dns.html
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