[Linux] DNS

What is DNS?

Domain Name System의 약자로 호스트의 도메인을 호스트의 네트워크 주소로 변환해주는 것

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DNS 구성 요소

1. Domain Name System
2. Name Server
3. Resolver

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DNS Record

Type	Full Name	Description
A	Host Record (IPv4)	FQDN과 32 bit의 IPv4로 연결
AAAA	Host Record (IPv6)	FQDN과 128 bit의 IPv6로 연결
CNAME	Alias Record (별칭)	실제 도메인 이름과 연결되는 가상 도메인 이름을 정의
SOA	Start Of Authority	권한 시작을 지정하며, 권한이 있는 서버를 가리킴
NS	Name Server	도메인 서버 목록을 지정
MX	Mail Exchange Record	주어진 사서함에 도달할 수 있는 라우팅 정보를 제공
SRV	Service Resources	비슷한 TCP/IP 서비스를 제공하는 다수의 서버 위치 정보를 제공

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Setting DNS

Forward

apt install -y bind9 bind9-utils bind9-dnsutils

vim /etc/resolv.conf
nameserver 192.168.0.1

vim /etc/bind/named.conf
zone  "naver.com"{
	type master;
	file "naver.zone";
};

vim /etc/bind/named.conf.options
dnssec-validation no;

cp /etc/bind/db.local /var/cache/bind/naver.zone

vim /var/cache/bind/naver.zone
:%s/localhost/ns.naver.com/g
   	IN	A	192.168.0.1
ns	IN	A	192.168.0.1
www	IN	A	192.168.0.2

systemctl restart bind9

Lookup

apt install -y bind9 bind9-utils bind9-dnsutils

vim /etc/resolv.conf
nameserver 192.168.0.1

vim /etc/bind/named.conf
zone  "0.168.192.in-addr.arpa"{
	type master;
	file "naver.re.zone";
};

vim /etc/bind/named.conf.options
dnssec-validation no;

cp /etc/bind/db.local /var/cache/bind/naver.zone

vim /var/cache/bind/naver.zone
:%s/localhost/ns.naver.com/g
   	IN	A	192.168.0.1
ns	IN	A	192.168.0.1
www	IN	A	192.168.0.2

cp /etc/bind/db.local /var/cache/bind/naver.re.zone

vim /var/cache/bind/naver.re.zone
:%s/localhost/ns.naver.com/g
1   IN	PTR ns.naver.com.

systemctl restart bind9

Master & Slave
Master

apt install -y bind9 bind9-utils bind9-dnsutils

vim /etc/resolv.conf
nameserver 192.168.0.1
search example.com
domain example.com

vim /etc/bind/named.conf
zone  "example.com" {
	type master;
	file "example.zone";
	allow-update { any; };
	allow-transfer { 192.168.0.2; };
};

zone  "0.168.192.in-addr.arpa" {
	type master;
	file "example.re.zone";
	allow-update { any; };
	allow-transfer { 192.168.0.2; };
};

vim /etc/bind/named.conf.options
dnssec-validation no;

cp /etc/bind/db.local /var/cache/bind/example.zone

vim /var/cache/bind/example.zone
:%s/localhost/Master.example.com/g
Master IN	A	192.168.0.1
ns	   IN	A	192.168.0.1
www	   IN	A	192.168.0.2

cp /etc/bind/db.local /var/cache/bind/naver.re.zone

vim /var/cache/bind/example.re.zone
:%s/localhost/ns.naver.com/g
1  IN	PTR	ns.example.com.

systemctl restart bind9

Slave

apt install -y bind9 bind9-utils bind9-dnsutils

vim /etc/resolv.conf
nameserver 192.168.0.2
search example.com
domain example.com

vim /etc/bind/named.conf
zone  "example.com" {
	type slave;
	masters { 192.168.0.1; };
	file "example.zone";
};

zone  "0.168.192.in-addr.arpa" {
	type slave;
	masters { 192.168.0.1; };
	file "example.re.zone";
};

systemctl restart bind9