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.
- Add the forward zone configuration:
vim /etc/named.conf
- 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"; };
- Run the
named-checkconf
command to verify the configuration.named-checkconf
- Insert the zone configuration just before the include statements at the bottom of the file:
- Add the forward zone configuration:
- Create the forward zone file and check the configuration for syntax errors with `named-checkzone`.
- Create the forward zone file and enter the following information:
vim /var/named/fwd.mylabserver.com.db
- 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 172.31.18.93 mailprod IN A 172.31.18.30 mailbackup IN A 172.31.18.72 ; Canonical Name/Alias dns IN CNAME nameserver.mylabserver.com. ; Mail Exchange Records @ IN MX 10 mailprod.mylabserver.com. @ IN MX 20 mailbackup.mylabserver.com.
- Run the named-checkzone command to check the zone file for syntax errors.
named-checkzone mylabserver.com /var/named/fwd.mylabserver.com.db
- Create the forward zone file and enter the following information:
- Change the file permissions and the group owner for `/var/named/fwd.mylabserver.com.db`.
- Change the file permissions for /var/named/fwd.mylabserver.com.db:
chmod 760 /var/named/fwd.mylabserver.com.db
- Change the group owner of the file to named.
chgrp named /var/named/fwd.mylabserver.com.db
- Change the file permissions for /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