I was studying how to set up DNS on a Cisco router, and I got confused on this piece that stated:

"Next step is to configure your DNS server with the host names of your local network, this way when Alan's PC trys to ping or connect to Wayne, the router will successfully resolve its netbios name to the appropriate IP address:"

From: https://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/257-cisco-router-dns-server.html

However, in the network diagram they provided, the hosts Alan and Wayne are already connected to one another via a switch. So they should be able to ping and send traffic to one another anyways (via MAC address). So what's the reason behind listing the hosts when setting up DNS?

3 Answers 3


Consistent DNS is basically a requirement for modern operating system use, especially on local area networks where inexperienced users will expect things to 'just work' without complicated configurations or manual intervention.

Having a DNS server for the network that can dynamically enter hostname entries for devices on the network, especially as they are given DHCP provided IP address configuration, can be critical for network resource sharing, automatic discovery of network shares or services, etc.

If you don't have a working DNS server for your network, you will be stuck with a level of functionality that is akin to how things worked back in the 90s or early 2000s for most people.


DNS service has nothing to do with the low level communication as L2 or L3 layer switches provide. If a host needs to communicate with another, they should be able to do so through L2 or(and) L3 layers without DNS service first.

If I may simplify things here, DNS service only provides a nice name for a long, nasty(?) address like ipv4 or ipv6 addresses. If you have more than hundreds of computers to connect, using names instead of addresses can be not just useful but very much needed.

Furthermore, you don't want to hard code an ip address for your service because ip address of a service can change when the service migrates to some other server and whatnot. DNS service solves this problem.

And there's more to DNS service than this.


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DNS is a service that resolves a host name to an IP address (via a DNS A record).

Using DNS enables Alan to run ping waynepc instead of having to memorize its IP address and using ping

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