Wondering how to configure BIND master DNS Server on CentOS 7? We can help you.

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Today, let us see steps performed by our Support Techs in order to configure BIND.

How to configure BIND master DNS Server on CentOS 7?

The Domain Name System (DNS) is a hierarchical distribute naming system for computers, services, or any resource connected to the Internet or a private network.

It associates various information with domain names assigned to each of the participating entities.

It translates domain names meaningful to humans into the numerical identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide.

Today, let us see the steps followed by our Support techs to perform this task.

Environment

Server Name: ns1example.com

IP Address: x.x.x.x

Install DNS (BIND)

BIND stands for Berkeley Internet Name Domain, a software that provides an ability to perform name to IP conversion.

yum -y install bind bind-utils

Configure DNS (BIND)

Configure it as given below:

include "/etc/rndc.key";
controls {
inet 127.0.0.1 allow { localhost; } keys { "rndc-key"; };
};
options {
recursion no;
directory "/var/named"; // the default
pid-file "/var/run/named/named.pid";
dump-file "data/cache_dump.db";
statistics-file "data/named_stats.txt";
allow-transfer { "none"; };
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
view "localhost_resolver" {
match-clients { 127.0.0.0/24; };
match-destinations { localhost; };
recursion yes;
zone "." IN {
type hint;
file "/var/named/named.ca";
};
include "/var/named/named.rfc1912.zones";
};
view "internal" {
match-clients { localnets; };
match-destinations { localnets; };
recursion yes;
zone "." IN {
type hint;
file "/var/named/named.ca";
};
zone "example.com" IN {
type master;
file "/var/named/example.com.db";
};
};
view "external" {
recursion no;
additional-from-cache no;
zone "." IN {
type hint;
file "/var/named/named.ca";
};
zone "example.com" IN {
type master;
file "/var/named/example.com.db";
};
};

Then, configure rfc1912.zones

cp -pv /etc/named.rfc1912.zones /var/named/named.rfc1912.zones

Create Zones

Edit /etc/named.conf.

vi /etc/named.conf

Create Zone Files

By default, zone lookup files are placed under /var/named directory.

Create a zone file called fwd.example.com.db for forward lookup under /var/named directory.

All domain names should end with a dot (.).

vi /var/named/example.com.db

There are some special keywords for Zone Files

A – A record
NS – Name Server
MX – Mail for Exchange
CNAME – Canonical Name

@ IN SOA ns1.example.com. root.example.com.

(
1001 ;Serial
3H ;Refresh
15M ;Retry
1W ;Expire
1D ;Minimum TTL
)

;Name Server Information

@ IN NS ns1.example.com.

;IP address of Name Server

ns1 IN A x.x.x.x

;Mail exchanger

example.com. IN MX 10 mail.example.com.

;A – Record HostName To IP Address

www IN A y.y.y.y

mail IN A z.z.z.z ;

CNAME record ftp IN CNAME www.example.com.

Whenever you update the zone lookup file, you need to change/increment the serial like 1002 ;Serial.

Once zone files are created, restart bind service.

systemctl restart named

Enable it on system startup.

systemctl enable named

Use the following command to verify the forward lookup.

dig www.example.com

Output: The DNS server should give 192.168.0.100 as ip for www.example.com.

; <<>> DiG 9.9.4-RedHat-9.9.4-74.el7_6.1 <<>> www.example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35563
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.example.com. IN A

;; ANSWER SECTION:
www.example.com. 86400 IN A y.y.y.y

;; AUTHORITY SECTION:
example.com. 86400 IN NS primary.example.com.

;; ADDITIONAL SECTION:
ns1.example.com. 86400 IN A x.x.x.x

;; Query time: 0 msec
;; SERVER: 192.168.0.10#53(192.168.0.10)
;; WHEN: Wed Jul 03 02:00:40 EDT 2019
;; MSG SIZE rcvd: 100

Install BIND utilities yum install -y bind-utils package to get nslookup or dig command.

Confirm the reverse lookup.

dig -x y.y.y.y

Output: The DNS server gives www.example.com as a name for y.y.y.y.

; <<>> DiG 9.9.4-RedHat-9.9.4-74.el7_6.1 <<>> -x y.y.y.y
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4807
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;100.0.168.192.in-addr.arpa. IN PTR

;; ANSWER SECTION:
100.0.168.192.in-addr.arpa. 86400 IN PTR www.example.com.

;; AUTHORITY SECTION:
0.168.192.in-addr.arpa. 86400 IN NS ns1.example.com.

;; ADDITIONAL SECTION:
ns1.example.com. 86400 IN A x.x.x.x

;; Query time: 0 msec
;; SERVER: x.x.x.x#53(x.x.x.x)
;; WHEN: Wed Jul 03 02:02:47 EDT 2019
;; MSG SIZE rcvd: 124

It is now confirmed that both forward and reverse lookups are working fine.

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Conclusion

In short, we saw steps followed by our Support Techs to Configure BIND master DNS Server on CentOS 7.