1 Basic Knowledge Points

DNS services

DNS domain name

DNS Domain Name Structure

DNS analysis

resource record

2 Basic Environment Installation

root:~ # yum install -y bind
root:~ # vim /etc/named.conf

• Modify these two lines to make all hosts accessible

  listen-on port 53 { localhost; };
  allow-query { any; }
  

root:/etc/named # systemctl start named.service

3 Master-slave Server Construction

Setting up the Main Server

• Modify the bind configuration file

vim /etc/named.conf
//  listen-on port 53 { 127.0.0.1; };
//  allow-query     { localhost; };  
allow-transfer {from server IP;};          #Only slave server synchronization is allowed

vim /etc/named.rfc1912.zones
//Add to
zone "qh.com" IN {
        type master;
        file "qh.com.zone";
}

• Editing DNS Regional Database Files

root:/etc/named # cp -p /var/named/named.localhost /var/named/qh.com.zone
root:/var/named $ vi /var/named/qh.com.zone
$TTL 1D
@       IN SOA  master qh.com. (
                                        2019042210      ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
                NS       master
master      A    192.168.64.151
dbserver1   A    1.1.1.1
dbserver2   A    2.2.2.2

root:~ # systemctl restart named.service #Restart service

• test

root:~ $ dig dbserver1.qh.com @192.168.64.151

Build slave server

yum install bind 
vim /etc/named.conf
//  listen-on port 53 { 127.0.0.1; };
//  allow-query     { localhost; };  
allow-transfer {none;};                                        #No machine synchronization allowed
vim /etc/named.rfc1912.zones
zone "qh.com" {
    type slave;
    masters {master server IP;};                                                                                         
    file "slaves/qh.com.slave";
};
root:~ # systemctl start named.service 

• Synchronize from the server

root:/var/named/slaves # cp -p /var/named/named.localhost /var/named/slave/qh.com.slave
root:/var/named # cd slaves/
root:/var/named/slaves # chmod g+w qh.com.slave 
root:/var/named/slaves # rndc reload
server reload successful
root:/var/named/slaves # ll
total 4
-rw-rw---- 1 root named 152 Jun 21  2007 qh.com.slave

• test

  root:~ $ vi /etc/sysconfig/network-scripts/ifcfg-ens33

  

root:~ $ service network restart 
Restarting network (via systemctl):                        [  OK  ]
root:~ $ cat /etc/resolv.conf
; generated by /usr/sbin/dhclient-script
search localdomain
nameserver 192.168.64.151
nameserver 192.168.64.152

• Disconnect 151 Network Card
• Testing on the client
  
• The address is resolved from the slave server. The master-slave server has succeeded.

4. Setting up the Reverse Main Server

• configuration file

zone "64.168.192.in-addr.arpa" IN {
        type master;    
        file "192.168.64.zone";
};

• Regional database files

root:/var/named $ cp -p qh.com.zone 192.168.64.zone
root:/var/named $ vim 192.168.64.zone
$TTL 1D
@ IN SOA master qh.com. ( 1 1H 10M 12H 1D )
     NS  master
master A 192.168.64.151
7    PTR websrv.qh.com.
6    PTR  websrv.qh.com.
100  PTR mail.qh.com.
root:~ $ rndc reload
root:~ $ systemctl restart named.service

• test
  
  

5 parent domain delegates subdomains to another server

• master server

  yum install bind 
  vim /etc/named.conf
  //  listen-on port 53 { 127.0.0.1; };
  //  allow-query     { localhost; };

• 192.168.64.153 on DNS servers in subdomains

root:/var/named # vi /etc/named.rfc1912.zones 
zone "beijing.qh.com" IN {
        type master;
        file "beijing.qh.com.zone";
};

root:/var/named # cp -p named.empty beijing.qh.com.zone
root:/var/named # chmod g+w beijing.qh.com.zone
root:~ $ vim /var/named/beijing.qh.com.zone
$TTL 1D
@   IN SOA  master beijing.qh.com. (
                    2019042214  ; serial
                    1D  ; refresh
                    1H  ; retry
                    1W  ; expire
                    3H )    ; minimum
            NS   master
master      A    192.168.64.153
websrv     A    3.3.3.3
www       CNAME  websrv    #Aliases can be used here

root:~ $ systemctl start named.service

• Test success
  

  6. Implementing Intelligent DNS

• Main DNS

root:~ # vim /etc/named.conf #Three different regional network segments
acl beijingnet{
        192.168.64.0/24;
};
acl shanghainet{
        192.168.65.0/24;
};
acl othernet{
        any;
};
view beijingview{
        match-clients {beijingnet;};
        include "/etc/named/named.rfc1912.zones.bj";
};
view shanghaiview{
        match-clients {shanghainet;};
        include "/etc/named/named.rfc1912.zones.sh";
};
view otherview{
        match-clients {othernet;};
        include "/etc/named.rfc1912.zones";
};

############################## The record at the beginning of the zone is placed in the / etc/named.rfc1912.zones file included in include

root:/var/named # cp -p qh.com.zone qh.com.bj    ##Creating Beijing and Shanghai Database
root:/var/named # cp -p qh.com.zone qh.com.sh

root:/var/named # cat qh.com.bj 
$TTL 1D
@   IN  SOA master qh.com ( 1 1D 1H 1W 3H )
        NS master
master  A  192.168.64.151
www     A  6.6.6.6

root:/var/named # vi qh.com.sh
$TTL 1D
@   IN  SOA master qh.com ( 1 1D 1H 1W 3H )
        NS master
master  A  192.168.64.151
www     A  7.7.7.7

root:/var/named # cp qh.com.sh qh.com.zone  #Other regional databases
cp: overwrite 'qh.com.zone'? y

root:/var/named # vi qh.com.zone 
$TTL 1D
@   IN  SOA master qh.com ( 1 1D 1H 1W 3H )
        NS master
master  A  192.168.64.151
www     A  8.8.8.8

• Three databases, corresponding to different regions
  

root:~ $ cp -p /etc/named.rfc1912.zones /etc/named/named.rfc1912.zones.bj
root:~ $ cp -p /etc/named.rfc1912.zones /etc/named/named.rfc1912.zones.sh

• A total of three regional database files
  
• Start associating databases

root:/etc/named # vi named.rfc1912.zones.bj

root:/etc/named # vi named.rfc1912.zones.sh

The original named.rfc1912.zones configuration remains unchanged

• Syntax check

• Restart service

#Report errors
root:/var/named # rndc reload
rndc: connect failed: 127.0.0.1#953: connection refused
# Try restarting the service before loading

• test
  DNS must be pointed to the assigned server
  
• DNS server has two ip segments
  

• With 64 network segments
  

• With 65 network segments
  
• Other network segments

  Add a network segment temporarily
   Server: IP a 192.168.63.1/24 dev ens33
   Client: IP a 192.168.63.2/24 dev ens33

• The tests were successful.
  

  7 Internet DNS Architecture Experiments

• Architecture diagram
  
• A total of 7 hosts to jointly implement the Internet dns architecture
  
• 1 Point client dns server to local dns server
  
• 2. Setting up the website

root:~ # yum install httpd
root:~ # cd /var/www/html/
root:/var/www/html # echo 192.168.64.57,hello >index.html
root:/var/www/html # chmod a+r index.html
root:/var/www/html # service httpd restart

• 3 client test
  

• 4 Configure Master DNS

root:~ # yum install bind
root:~ # vi /etc/named.conf
//      listen-on port 53 { 127.0.0.1; };
//      allow-query     { localhost; };
allow-transfer {192.168.64.47;}; 
root:~ # vi /etc/named.rfc1912.zones
zone "qh.com" IN {
        type master;
        file "qh.com.zone";
};

root:~ # cd /var/named/
root:/var/named # vi qh.com.zone
$TTL 1D
@ IN SOA ns1 qh.mail.com. ( 1 1H 10M 1D 3H )
        NS ns1
        NS ns2

ns1 A 192.168.64.37
ns2 A 192.168.64.47
www A 192.168.64.57

root:/var/named # chgrp named qh.com.zone
root:/var/named # chmod 640 qh.com.zone
#### Syntax check
root:/var/named # named-checkconf
#### Startup service
root:/var/named # systemctl start named.service

• 5 client test master server
  
• 6. Build slave server

root:~ # yum install bind
root:~ # vi /etc/named.conf
//      listen-on port 53 { 127.0.0.1; };
//      allow-query     { localhost; };
allow-transfer {none;}; 
root:~ # vi /etc/named.rfc1912.zones
zone "qh.com" {
    type slave;
    masters {192.168.64.37;};                                              
    file "slaves/qh.com.slave";
};
root:/var/named/slaves # systemctl start named.service 
root:/var/named/slaves # rndc reload                   
root:/var/named/slaves # ll
total                                  #Already synchronized
-rw-r--r-- 1 named named 269 Apr 23 16:34 qh.com.slave

• 7 Test Slave Server
  
• 8 Configuration of com domain server

root:~ # yum install bind
root:~ # vi /etc/named.conf
//      listen-on port 53 { 127.0.0.1; };
//      allow-query     { localhost; };
allow-transfer {none;}; 
------------------------------------------------
root:~ # vi /etc/named.rfc1912.zones
zone "com" IN {
        type master;
        file "com.zone";
};
---------------------------------------------------------
root:~ # cd /var/named/
root:/var/named # vim com.zone
$TTL 1D
@ IN SOA NS1 qh.mail.com. (1 1D 1H 1W 3D )
        NS ns1
qh      NS qhns1
qh      NS qhns2
ns1 A 192.168.64.27
qhns1 A 192.168.64.37   #master server
qhns2 A 192.168.64.47   #from server

root:/var/named # chgrp named com.zone 
root:/var/named # chmod g+w com.zone 
root:/var/named # systemctl start named.service 
root:/var/named # rndc reload
server reload successful

• 9 tests (passed the parent field 192.168.64.27 test)
  
• 10 Build Root DNS

root:~ # yum install bind
root:~ # vi /etc/named.conf
//      listen-on port 53 { 127.0.0.1; };
//      allow-query     { localhost; };
zone "." IN {
        type master;          #Change to master's own roots
        file "root.zone";
};

root:~ # cd /var/named/
root:/var/named # vim root.zone
$TTL 1D
@ IN SOA ns1 qh.mail.com. (1 1D 1H 1W 3D )
        NS ns1
com     NS comns1
ns1 A 192.168.64.17
comns1 A 192.168.64.27

root:/var/named # chgrp named com.zone 
root:/var/named # chmod g+w com.zone 
root:/var/named # systemctl start named.service 

• Testing 11 (through the primary server test)
  
• 12 Configuring Local dns Server

root:~ # yum install bind
root:~ # vi /etc/named.conf
//      listen-on port 53 { 127.0.0.1; };
//      allow-query     { localhost; };

root:/etc/sysconfig/network-scripts # vi /var/named/named.ca #Change to the following configuration
.                       518400  IN      NS      a.root-servers.net.

a.root-servers.net.     3600000 IN      A       192.168.64.17

• 13 clear cache

  root:/var/named # rndc flush #Clean up all dns caches

• 14 Modify security configuration in local dns

root:~ # vi /etc/named.conf 
dnssec-enable no;
dnssec-validation no;

• 15 test
  

Errors that may occur in some processes

root:/var/named # systemctl start named.service
Job for named.service failed because the control process exited with error code. See "systemctl status named.service" and "journalctl -xe" for details.

You can generally view the current error type through the system CTL status named. Service - L command

#dig A example.com
; <<>> DiG 9.9.4-RedHat-9.9.4-14.el7 <<>> A example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30523
...
SERVFAIL:The nameserver encountered a problem while processing the query.
• May use dig +trace Errors can be caused by networks and firewalls
NXDOMAIN: The queried name does not exist in the zone.
• May be CNAME Corresponding A The absence of records results in
REFUSED: The nameserver refused the client's DNS request due to policy
restrictions.
• May be DNS Strategy led
• NOERROR It doesn't mean there's no problem. It can also be an outdated record.
•See if it is an authoritative record. flags:aa Mark judgement
•Deleted records can still return results, possibly because*Record existence
•Such as:*.example.com． IN A 172.25.254.254
•Pay attention to "."Use
•avoid CNAME point CNAME Records, which may result in loops
•est.example.com. IN CNAME lab.example.com.
•lab.example.com. IN CNAME test.example.com.
•Correct configuration PTR Recording, many Service Dependencies PTR，as sshd,MTA
•Correctly configure polling round-robin Record