Difference between revisions of "DNS server unique zone"
 
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[[Category:Linux]]
 
[[Category:Linux]]
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The DNS [Domain Name System] is a key component of a network infrastructure. '''It allows you to use NAMES''' instead of IP addresses and technical garbage.
 
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You can learn how it works through a simple Google request.
 
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Here, I will present the installation of:  
 
Here, I will present the installation of:  
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* '''DNS primary server''' (= DNS for domain smartcards.local) using ''BIND9''
 
 
* Local domain (.local)
 
* Local domain (.local)
  
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That means '''all the INTERNAL resources are private'''. Nothing is reachable from the outside.
  
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You can re-use all this content for a web-site or public domain. Just replace ''smartcards.local'' by ''mywebsite.com''.
 
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=Primary master=
 
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A DNS primary master is the main DNS for your local domain (ex: smartcards.local).
 
  
  
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These are the steps to do:
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In the following example I'll be using:
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* '''Set the external DNS''' to use by your server
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* INTERNAL zone: ''smartcards.'''local'''''  
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**File: /etc/bind/named.conf.options
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* DNS server name: ''smartcard-gw''
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* Network: 172.16.50.0/24 ; router: 172.16.50.1 ; DNS server IP: 172.16.50.2
  
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* '''Declare the new domain''' to manage
 
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** File: /etc/bind/named.conf.local
 
  
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* Create a '''dedicated configuration file''' for the new domain
 
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** New file: /etc/bind/smartcards.local
 
  
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* Adjust the '''reverse zone'''
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=Zone configuration (name to IP @)=
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** File: /etc/bind/named.conf.local
 
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** Rename and adjust file: /etc/bind/db.192
 
  
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==Declare the new zone==
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==Declare the new domain==
 
  
 
Edit configuration file:
 
Edit configuration file:
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Uncomment and adjust the file content
 
Uncomment and adjust the file content
  
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<syntaxhighlight lang="bash">
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<syntaxhighlight lang="apache">
 
zone "smartcards.local" {
 
zone "smartcards.local" {
 
type master;
 
type master;
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==Domain configuration file==
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==Zone configuration file==
  
  
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Create the domain configuration file from a local template:
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Create the zone configuration file from a local template:
  
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
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Adjust the file content
 
Adjust the file content
  
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<syntaxhighlight lang="bash">
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<syntaxhighlight lang="apache">
 
;
 
;
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; BIND data file for smartcards.local (you can use mywebsite.com)
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; BIND data file for smartcards.local
 
;
 
;
 
$TTL    604800
 
$TTL    604800
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@                IN      NS      smartcard-gw.smartcards.local.
 
@                IN      NS      smartcard-gw.smartcards.local.
 
smartcard-gw    IN      A      172.16.50.2
 
smartcard-gw    IN      A      172.16.50.2
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;
 
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; -- alternative --
 
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; To declare a server a specific domain only
 
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;
 
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;website.com      IN      NS      smartcard-gw.website.com.
 
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;website.com      IN      A      172.16.50.2
 
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;
 
;
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==Reverse zone file==
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=Reverse zone (IP @ to name)=
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Now that the zone is setup and resolving names to IP Adresses a '''Reverse zone''' is also required. A Reverse zone allows DNS to resolve an address to a name.
 
Now that the zone is setup and resolving names to IP Adresses a '''Reverse zone''' is also required. A Reverse zone allows DNS to resolve an address to a name.
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Add the following reverse
 
Add the following reverse
  
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<syntaxhighlight lang="bash">
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<syntaxhighlight lang="apache">
 
# Our reverse zone
 
# Our reverse zone
 
# Server IP 172.16.50.2
 
# Server IP 172.16.50.2
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===Configure reverse zone===
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==Configure reverse zone==
  
  
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The content is basically the same as /etc/bind/smartcards.local:
 
The content is basically the same as /etc/bind/smartcards.local:
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<syntaxhighlight lang="bash">
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<syntaxhighlight lang="apache">
 
;
 
;
 
; BIND reverse data file for local 172.16.50.XXX net
 
; BIND reverse data file for local 172.16.50.XXX net
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==Take changes into account==
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=Take changes into account=
  
  
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</syntaxhighlight>
 
</syntaxhighlight>
  
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==DNS server logs==
 
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Logs are in '''/var/log/syslog'''
 
  
  
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Add a A or AAAA entry:
 
Add a A or AAAA entry:
  
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<syntaxhighlight lang="bash">
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<syntaxhighlight lang="apache">
 
my-new-host      IN      A      172.16.50.60
 
my-new-host      IN      A      172.16.50.60
 
</syntaxhighlight>
 
</syntaxhighlight>
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Add a A or AAAA entry:
 
Add a A or AAAA entry:
  
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<syntaxhighlight lang="bash">
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<syntaxhighlight lang="apache">
 
60      IN      PTR    my-new-host.smartcards.local.
 
60      IN      PTR    my-new-host.smartcards.local.
 
</syntaxhighlight>
 
</syntaxhighlight>
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service bind9 restart
 
service bind9 restart
 
</syntaxhighlight>
 
</syntaxhighlight>
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Latest revision as of 14:16, 22 August 2014


Here, I will present the installation of:

  • Local domain (.local)

That means all the INTERNAL resources are private. Nothing is reachable from the outside.


In the following example I'll be using:

  • INTERNAL zone: smartcards.local
  • DNS server name: smartcard-gw
  • Network: 172.16.50.0/24 ; router: 172.16.50.1 ; DNS server IP: 172.16.50.2


Zone configuration (name to IP @)

Declare the new zone

Edit configuration file: 

vim /etc/bind/named.conf.local


Uncomment and adjust the file content 

zone "smartcards.local" {
	type master;
        file "/etc/bind/smartcards.local";
};


Zone configuration file

Create the zone configuration file from a local template: 

cp /etc/bind/db.local /etc/bind/smartcards.local


Edit configuration file: 

vim /etc/bind/smartcards.local


Adjust the file content 

;
; BIND data file for smartcards.local
;
$TTL    604800
@       IN      SOA     smartcard-gw.smartcards.local. root.smartcards.local. (
                       20140603         ; Serial
                                        ; As the serial be changed everytime you edit this file
                                        ; it is recommended to use the pattern "yyyyMMdd"
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL

; 
; DNS server declaration
; Each NS must point to an A record, not a CNAME. 
; This is where the Primary and Secondary DNS servers are defined
;
@                IN      NS      smartcard-gw.smartcards.local.
smartcard-gw     IN      A       172.16.50.2

;
; Gateway (router)
;
cisco-router      IN      A       172.16.50.1

;
; Declare your servers and networks hosts 
;
smarcartd-prod-00 IN      A       172.16.50.50
smarcartd-prod-01 IN      A       172.16.50.51
smarcartd-prod-02 IN      A       172.16.50.52
smarcartd-prod-03 IN      A       172.16.50.53

; Create an alias to an existing record
;wwww             IN      CNAME   smartcard-gw


Notes:

  • Don't forget to adjust the serial every-time you edit the file !
  • NS = Name server
  • A = IP v4 entry
  • AAAA = IP v6 entry
  • CNAME = Alias to a previous A or AAAA entry


Reverse zone (IP @ to name)

Now that the zone is setup and resolving names to IP Adresses a Reverse zone is also required. A Reverse zone allows DNS to resolve an address to a name.


Declare reverse zone

Edit configuration file: 

vim /etc/bind/named.conf.local


Add the following reverse 

# Our reverse zone
# Server IP 172.16.50.2
zone "50.16.172.in-addr.arpa" {
        type master;
        file "/etc/bind/db.172";
};


Key points:

  • Replace 50.16.172 with the first three octets of whatever network you are using - in reverse order!
  • Name the zone file /etc/bind/db.172 : it should match the first octet of your network.


Configure reverse zone

Now create the /etc/bind/db.172 file: 

cp /etc/bind/db.127 /etc/bind/db.172


Edit the new file: 

vim /etc/bind/db.172


The content is basically the same as /etc/bind/smartcards.local: 

;
; BIND reverse data file for local 172.16.50.XXX net
;
$TTL    604800
@       IN      SOA     smartcard-gw.smartcards.local. root.smartcards.local. (
                       20140603         ; Serial
                                        ; As the serial be changed everytime you edit this file
                                        ; it is recommended to use the pattern "yyyyMMdd"
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
; Local server
;
@       IN      NS      smartcard-gw.
2       IN      PTR     smartcard-gw.smartcards.local.

; Gateway (router)
1       IN      PTR     cisco-router.smartcards.local

;
; Other components and hosts
;
50       IN      PTR     smartcard-prod-00.smartcards.local.
51       IN      PTR     smartcard-prod-01.smartcards.local.
52       IN      PTR     smartcard-prod-02.smartcards.local.
53       IN      PTR     smartcard-prod-03.smartcards.local.


Notes:

  • Don't forget to adjust the serial every-time you edit the file !
  • You only need to put the last byte value in the reverse
  • PTR = redirection to A entry


Take changes into account

service bind9 restart



Add new hostname

This is how we had a new host-name into the network:


Update LOCAL zone

Edit local zone: 

vim /etc/bind/smartcards.local


Add a A or AAAA entry: 

my-new-host       IN      A       172.16.50.60


Update REVERSE zone

Edit local zone: 

vim /etc/bind/db.172


Add a A or AAAA entry: 

60       IN      PTR     my-new-host.smartcards.local.


Restart service

service bind9 restart




Sources

You can find a lot of information about DNS on the web. I used the following tutorials:


Bug fixes:

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