DNS Server Config CentOS 8

1. Configure the firewall

firewall-cmd --permanent --zone=public --add-service=dns

firewall-cmd --reload        

2. Domain name: knowhere

3. change to bootproto=static in ifcfg file

3. change hostname

hostnamectl set-hostname srvcent01.knowhere        

4. Make sure /etc/resolv.conf contains

search knowhere

nameserver 10.0.0.63        

5. add dns=none in /etc/NetworkManager/NetworkManager.conf

6. Configure Single DNS Server (authoritative)

vi /etc/named.conf (chmod 644 named.conf)

#### The text below is the content of named.conf file
listen-on port 53 { localhost; 192.168.56.4; };
#listen-on-v6 port 53 { ::1; };
allow-query { 127.0.0.1; 192.168.56.0/24; };
recursion no;        

7.

vi named.rfc1912.zones
#### The text below is the content of named.rfc1912.zones file

zone “knowhere” IN {
type master;
file “forward.zone”;
allow-update { none; };
};
zone “4.56.168.192.in-addr.arpa” IN {
type master;
file “reverse.zone”;
allow-update { none; };
};        

The option allow-update refers to DNS dynamic updates, that means an application in a host can add a DNS record; for security reasons this is disabled by default and therefore only the system administrator can add records manually.

8. Add forward and reverse lookup files.?/var/named/forward.zone?and?/var/named/reverse.zone

forward.zone — add?these lines (VERY IMPORTANT: every IN should have one whitespace before it. All other lines should start with NO whitespace. Whitespace has a special meaning in bind zone files.)

$TTL 1D

@                          IN SOA srvcent01.knowhere. root.knowhere.   (
2019022400 ; serial
3h         ; refresh
15         ; retry
1w         ; expire
3h         ; minimum
)
 IN NS srvcent01.knowhere.
srvcent01 IN A 192.168.56.4        

reverse.zone — add these lines: (VERY IMPORTANT: every IN should have one whitespace before it. All other lines should start with NO whitespace. Whitespace has a special meaning in bind zone files.)

?$TTL 1D

@ IN SOA srvcent01.knowhere. root.knowhere. (
2019022400 ; serial
3h ; refresh
15 ; retry
1w ; expire
3h ; minimum
)
 IN NS srvcent01.knowhere.
4 IN PTR srvcent01.knowhere        

Results

If done correctly, the following command looks like this:

[root@srvcent01 named]# named-checkzone knowhere forward.zone

zone knowhere/IN: loaded serial 2019022400
OK        

Now, lets take a look at the client side configuration.

CLIENT SIDE CONFIGURATION

The following configuration is done on any server that will use the above server as DNS server to talk to other servers in the environment.

1. Add nameserver IP in /etc/resolv.conf
2. Add search domain in /etc/resolv.conf

[root@srvcent03 network-scripts]# cat /etc/resolv.conf
 # Generated by NetworkManager
 search knowhere
 nameserver 10.0.2.3        

3. add dns=none in networkmanager.conf

[root@srvcent03 network-scripts]# cat /etc/NetworkManager/NetworkManager.conf | tail -3
 #level=TRACE
 #domains=ALL
 dns=none
 [root@srvcent03 network-scripts]# hostname
 srvcent03.knowhere
 [root@srvcent03 network-scripts]#        

4. add DNS=192.168.56.4 (DNS Server) in ifcfg file and restart NetworkManager

[root@srvcent03 network-scripts]# cat ifcfg-vbox 
 TYPE=Ethernet
 PROXY_METHOD=none
 BROWSER_ONLY=no
 BOOTPROTO=none
 IPADDR=192.168.56.5
 PREFIX=24
 GATEWAY=255.255.255.0
 DEFROUTE=yes
 IPV4_FAILURE_FATAL=no
 IPV6_DISABLED=yes
 IPV6INIT=no
 NAME=vbox
 UUID=d4664dd4–0e11–477c-bb0b-9d208e64130d
 DEVICE=vbox
 ONBOOT=yes
 DNS=192.168.56.4
 [root@srvcent03 network-scripts]# systemctl restart NetworkManager        

5. Verify

[root@srvcent03 network-scripts]# nslookup srvcent03
 Server: 10.0.2.3
 Address: 10.0.2.3#53
 
 Non-authoritative answer:
 Name: srvcent03
 Address: 192.168.100.8
 Name: srvcent03
 Address: 192.168.56.5

 [root@srvcent03 network-scripts]# nslookup srvcent05
 Server: 10.0.2.3
 Address: 10.0.2.3#53
 
 Non-authoritative answer:
 Name: srvcent05
 Address: 192.168.100.9
 
 [root@srvcent03 network-scripts]#        

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