DNS: Create a Forward Zone

15 minutes
  • 5 Learning Objectives

About this Hands-on Lab

Zones and zone files are key components in configuring DNS servers. In this lab, we will configure a forward zone and a forward zone file, then add TTL, SOA, NS, and A records. Next, we will run a syntax check on the `named.conf` and the forward zone file with `named-checkconf` and `named-checkzone`, respectively. This allows a name server to resolve a query, given the hostname, and returns the IP address. This is the most common type of DNS query.

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Add the forward zone configuration to the `/etc/named.conf` file. Then run the `named-checkconf` command to verify the configuration.
  1. Add the forward zone configuration:
    vim /etc/named.conf
    1. Insert the zone configuration just before the include statements at the bottom of the file:
      zone "mylabserver.com" {
      type master;
      file "/var/named/fwd.mylabserver.com.db";
    2. Run the named-checkconf command to verify the configuration.
Create the forward zone file and check the configuration for syntax errors with `named-checkzone`.
  1. Create the forward zone file and enter the following information:
    vim /var/named/fwd.mylabserver.com.db
  2. Enter in the following:
    $TTL    86400
    @       IN      SOA     nameserver.mylabserver.com. root.mylabserver.com. (
                          10030         ; Serial
                           3600         ; Refresh
                           1800         ; Retry
                         604800         ; Expiry
                          86400         ; Minimum TTL
    ; Name Server
    @        IN      NS       nameserver.mylabserver.com.
    ; A Record Definitions
    nameserver       IN      A
    mailprod         IN      A
    mailbackup       IN      A
    ; Canonical Name/Alias
    dns        IN    CNAME    nameserver.mylabserver.com.
    ; Mail Exchange Records
    @        IN    MX    10    mailprod.mylabserver.com.
    @        IN    MX    20    mailbackup.mylabserver.com.
  3. Run the named-checkzone command to check the zone file for syntax errors.
    named-checkzone mylabserver.com /var/named/fwd.mylabserver.com.db
Change the file permissions and the group owner for `/var/named/fwd.mylabserver.com.db`.
  1. Change the file permissions for /var/named/fwd.mylabserver.com.db:
    chmod 760 /var/named/fwd.mylabserver.com.db
  2. Change the group owner of the file to named.
    chgrp named /var/named/fwd.mylabserver.com.db
Restart the named service.
systemctl restart named
Run a query to test the configuration.
nslookup mailprod.mylabserver.com localhost

Additional Resources

ABC Company is currently in the process of setting up its own internally-hosted DNS service. The next phase of the project is to create the forward zone files. The DNS administrator fell sick and is unavailable, but the project has a tight timeline. We have been designated as a resource to create the forward zone files until the DNS Administrator returns.

To complete this lab, we need to use the vim command to create and open a forward zone file and create the following records:

  • TTL Record
  • SOA Record
  • A Records:
    • nameserver
    • mailprod
    • mailbackup
  • CNAME Record:
    • dns = nameserver.mylabserver.com.

What are Hands-on Labs

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.

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