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Network+ lab 14 of 27

DNS: records and lookups with forwarding and the hosts file

Run name resolution for an office. You publish A, AAAA, MX and NS records, look them up forwards and backwards with nslookup and dig, forward unknown names to an upstream server, and see how the hosts file overrides DNS and quietly causes faults.

Run this lab

It needs Lite: its 4 nodes are set to 4 vCPU and 2,560 MB in total. That fits the free demo too.

In your workspace: Shared, then CompTIA Network Plus N10-009 guided labs, then 14 - DNS - records and lookups with forwarding and the hosts file

Try it free for 30 minutesRun it on Lite from £3 a day

The free demo needs no card and no email. Every lab plan includes every guided lab.

Level
Intermediate
Time
About 55 minutes
Nodes need
4 vCPU, 2,560 MB
Smallest plan
Lite

The scenario

Harbour Logistics wants staff to use names instead of addresses: the intranet www, the mail server, and the file server. Partners' names must resolve too. Today nothing has a name. You'll publish the company's records on R1, make R1 forward everything else to the provider's server R2, and learn to prove and troubleshoot name resolution from the client side.

Name (harbour.lab)TypeValue
wwwA10.10.10.80
wwwAAAA2001:db8:10::80
mailA10.10.10.25
filesA10.10.10.30
ns1A10.10.10.1
harbour.labMX10 mail.harbour.lab
harbour.labNSns1.harbour.lab

H1 gets its address, DNS server (10.10.10.1) and search domain (harbour.lab) from R1 by DHCP. NETOPS has dig.

What you’ll practise

  • Explain DNS resolution: stub resolver, recursive resolver, authoritative server, caching and TTL
  • Publish A, AAAA, MX and NS records and use automatic reverse (PTR) lookups
  • Query each record type with nslookup and dig, and read dig's flags and sections
  • Forward unknown names to an upstream server
  • Use and troubleshoot the hosts file
  • Describe DNSSEC, DNS over HTTPS and DNS over TLS

The tasks

  1. Look at the client side
  2. Publish the records
  3. Query every record type
  4. Reverse lookups
  5. Forward everything else upstream
  6. The hosts file, and how it bites
  7. Securing DNS

The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.

Topology and devices

The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.

Topology of DNS - records and lookups with forwarding and the hosts file4 nodes and 1 network, 4 links. Every link is listed as text below the diagram.R1R2H1NETOPSOffice-LANGi0/0eth0eth0Gi0/1Gi0/0
4 nodes and 1 network, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R1 Gi0/0 to Office-LAN (network)
  • H1 eth0 to Office-LAN (network)
  • NETOPS eth0 to Office-LAN (network)
  • R1 Gi0/1 to R2 Gi0/0
Nodes in DNS: records and lookups with forwarding and the hosts file, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
R1Cisco IOSvvios-adventerprisek9-m.SPA.159-3.M61 vCPU, 512 MB
R2Cisco IOSvvios-adventerprisek9-m.SPA.159-3.M61 vCPU, 512 MB
H1Alpine Linuxclbalpinebase-alpine-base-3-20-31 vCPU, 512 MB
NETOPSEVE-NG GUI server (Docker)eve-gui-server:latest1 vCPU, 1,024 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder CompTIA Network Plus N10-009 guided labs.

  3. Open 14 - DNS - records and lookups with forwarding and the hosts file and start its nodes, then open Lab Tasks for the scenario and the steps.

The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.

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CloudLabBox is independent of CompTIA, Cisco and Netgate. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.