Difference between revisions of "DNS server unique zone"

 
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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.
+
[[Category:Linux]]
 
 
You can learn how it works through a simple Google request.
 
 
 
  
 
Here, I will present the installation of:  
 
Here, I will present the installation of:  
* '''DNS primary server''' (= DNS for domain smartcards.local) using ''BIND9''
 
 
* Local domain (.local)
 
* Local domain (.local)
  
 +
That means '''all the INTERNAL resources are private'''. Nothing is reachable from the outside.
  
  
You can re-use all this content for a web-site or public domain. Just replace ''smartcards.local'' by ''mywebsite.com''.
 
 
 
 
 
=Setup=
 
 
<syntaxhighlight lang="bash">
 
apt-get install bind9 dnsutils bind9-doc
 
</syntaxhighlight>
 
 
 
 
=Primary master=
 
 
A DNS primary master is the main DNS for your local domain (ex: smartcards.local).
 
 
 
These are the steps to do:
 
* '''Set the external DNS''' to use by your server
 
**File: /etc/bind/named.conf.options
 
 
* '''Declare the new domain''' to manage
 
** File: /etc/bind/named.conf.local
 
 
* Create a '''dedicated configuration file''' for the new domain
 
** New file: /etc/bind/smartcards.local
 
 
* Adjust the '''reverse zone'''
 
** File: /etc/bind/named.conf.local
 
** Rename and adjust file: /etc/bind/db.192
 
 
 
==Set the external DNS==
 
 
This is the list of DNS your server will use to populate its own cache.
 
  
 +
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
  
The external DNS can either be your ISP's DNS or Google's servers.
 
  
!! Mind the order !!
 
First DNS have a higher priority.
 
  
 +
=Zone configuration (name to IP @)=
  
 
+
==Declare the new zone==
Edit configuration file:
 
 
 
<syntaxhighlight lang="bash">
 
vim /etc/bind/named.conf.options
 
</syntaxhighlight>
 
 
 
 
 
Uncomment and adjust the file content
 
 
 
<syntaxhighlight lang="bash">
 
[...]
 
forwarders {
 
    # Local gateway or router
 
    172.16.50.1;
 
 
 
    # Your ISP DNS IP’s
 
    182.176.39.23;
 
    182.176.18.13;
 
 
 
    # Google's DNS
 
    8.8.8.8
 
    8.8.4.4
 
};
 
[...]
 
</syntaxhighlight>
 
 
 
 
 
 
 
==Declare the new domain==
 
  
 
Edit configuration file:
 
Edit configuration file:
Line 94: Line 28:
 
Uncomment and adjust the file content
 
Uncomment and adjust the file content
  
<syntaxhighlight lang="bash">
+
<syntaxhighlight lang="apache">
 
zone "smartcards.local" {
 
zone "smartcards.local" {
 
type master;
 
type master;
Line 103: Line 37:
  
  
==Domain configuration file==
+
==Zone configuration file==
  
  
Create the domain configuration file from a local template:
+
Create the zone configuration file from a local template:
  
 
<syntaxhighlight lang="bash">
 
<syntaxhighlight lang="bash">
Line 122: Line 56:
 
Adjust the file content
 
Adjust the file content
  
<syntaxhighlight lang="bash">
+
<syntaxhighlight lang="apache">
 
;
 
;
; BIND data file for smartcards.local (you can use mywebsite.com)
+
; BIND data file for smartcards.local
 
;
 
;
 
$TTL    604800
 
$TTL    604800
@      IN      SOA    smartcards.local. root.smartcards.local. (
+
@      IN      SOA    smartcard-gw.smartcards.local. root.smartcards.local. (
                  201406031132         ; Serial
+
                      20140603         ; Serial
 
                                         ; As the serial be changed everytime you edit this file
 
                                         ; As the serial be changed everytime you edit this file
                                         ; it is recommended to use the pattern "yyyyMMddHHmm"
+
                                         ; it is recommended to use the pattern "yyyyMMdd"
 
                         604800        ; Refresh
 
                         604800        ; Refresh
 
                           86400        ; Retry
 
                           86400        ; Retry
 
                         2419200        ; Expire
 
                         2419200        ; Expire
 
                         604800 )      ; Negative Cache TTL
 
                         604800 )      ; Negative Cache TTL
 +
 
;  
 
;  
 
; DNS server declaration
 
; DNS server declaration
 
; Each NS must point to an A record, not a CNAME.  
 
; Each NS must point to an A record, not a CNAME.  
 
; This is where the Primary and Secondary DNS servers are defined
 
; This is where the Primary and Secondary DNS servers are defined
                IN      NS      smartcard-gw.smartcards.local
+
;
                IN      A      172.16.50.2
+
@                IN      NS      smartcard-gw.smartcards.local.
 
smartcard-gw    IN      A      172.16.50.2
 
smartcard-gw    IN      A      172.16.50.2
  
 
;
 
;
; -- alternative --
+
; Gateway (router)
; To declare a server a specific domain only
+
;
;website.com      IN      NS      smartcard-gw.website.com
+
cisco-router     IN      A      172.16.50.1
;website.com     IN      A      172.16.50.2
 
  
 +
;
 
; Declare your servers and networks hosts  
 
; Declare your servers and networks hosts  
smarcartd-prod-00 IN      A      172.16.50.10
+
;
smarcartd-prod-01 IN      A      172.16.50.11
+
smarcartd-prod-00 IN      A      172.16.50.50
smarcartd-prod-02 IN      A      172.16.50.12
+
smarcartd-prod-01 IN      A      172.16.50.51
smarcartd-prod-03 IN      A      172.16.50.13
+
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
 
; Create an alias to an existing record
Line 176: Line 112:
  
  
==Reverse zone file==
+
=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.
 
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.
Line 194: Line 129:
 
Add the following reverse
 
Add the following reverse
  
<syntaxhighlight lang="bash">
+
<syntaxhighlight lang="apache">
 
# Our reverse zone
 
# Our reverse zone
 
# Server IP 172.16.50.2
 
# Server IP 172.16.50.2
Line 212: Line 147:
  
  
===Configure reverse zone===
+
==Configure reverse zone==
  
  
Line 230: Line 165:
  
 
The content is basically the same as /etc/bind/smartcards.local:
 
The content is basically the same as /etc/bind/smartcards.local:
<syntaxhighlight lang="bash">
+
<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
Line 236: Line 171:
 
$TTL    604800
 
$TTL    604800
 
@      IN      SOA    smartcard-gw.smartcards.local. root.smartcards.local. (
 
@      IN      SOA    smartcard-gw.smartcards.local. root.smartcards.local. (
                    201406031301      ; Serial
+
                      20140603        ; Serial
 
                                         ; As the serial be changed everytime you edit this file
 
                                         ; As the serial be changed everytime you edit this file
                                         ; it is recommended to use the pattern "yyyyMMddHHmm"
+
                                         ; it is recommended to use the pattern "yyyyMMdd"
 
                         604800        ; Refresh
 
                         604800        ; Refresh
 
                           86400        ; Retry
 
                           86400        ; Retry
Line 245: Line 180:
 
;
 
;
 
; Local server
 
; Local server
 +
;
 
@      IN      NS      smartcard-gw.
 
@      IN      NS      smartcard-gw.
 
2      IN      PTR    smartcard-gw.smartcards.local.
 
2      IN      PTR    smartcard-gw.smartcards.local.
; Other servers
+
 
10       IN      PTR    smartcard-prod-00.smartcards.local.
+
; Gateway (router)
11       IN      PTR    smartcard-prod-01.smartcards.local.
+
1      IN      PTR    cisco-router.smartcards.local
12       IN      PTR    smartcard-prod-02.smartcards.local.
+
 
13       IN      PTR    smartcard-prod-03.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.
  
 
</syntaxhighlight>
 
</syntaxhighlight>
Line 259: Line 201:
  
 
* Don't forget to adjust the serial every-time you edit the file !  
 
* Don't forget to adjust the serial every-time you edit the file !  
 
* Note the difference in the "SOA"
 
** domain configuration (previous) : smartcards.local root.smartcards.local
 
** Reverse configuration : '''smartcard-gw'''.smartcards.local root.smartcards.local
 
  
 
* You only need to put the last byte value in the reverse  
 
* You only need to put the last byte value in the reverse  
Line 270: Line 208:
  
  
==Take changes into account==
+
=Take changes into account=
  
  
Line 276: Line 214:
 
service bind9 restart
 
service bind9 restart
 
</syntaxhighlight>
 
</syntaxhighlight>
 +
 +
 +
 +
 +
 +
=Add new hostname=
 +
 +
 +
This is how we had a new host-name into the network:
 +
 +
 +
==Update LOCAL zone==
 +
 +
 +
Edit local zone:
 +
 +
<syntaxhighlight lang="bash">
 +
vim /etc/bind/smartcards.local
 +
</syntaxhighlight>
 +
 +
 +
Add a A or AAAA entry:
 +
 +
<syntaxhighlight lang="apache">
 +
my-new-host      IN      A      172.16.50.60
 +
</syntaxhighlight>
 +
 +
 +
 +
==Update REVERSE zone==
 +
 +
 +
Edit local zone:
 +
 +
<syntaxhighlight lang="bash">
 +
vim /etc/bind/db.172
 +
</syntaxhighlight>
 +
 +
 +
Add a A or AAAA entry:
 +
 +
<syntaxhighlight lang="apache">
 +
60      IN      PTR    my-new-host.smartcards.local.
 +
</syntaxhighlight>
 +
 +
 +
 +
==Restart service==
 +
 +
<syntaxhighlight lang="bash">
 +
service bind9 restart
 +
</syntaxhighlight>
 +
 +
 +
 +
 +
 +
 +
=Sources=
 +
 +
You can find a lot of information about DNS on the web. I used the following tutorials:
 +
 +
* https://help.ubuntu.com/community/BIND9ServerHowto
 +
 +
* https://help.ubuntu.com/14.04/serverguide/dns-references.html#dns-record-types
 +
 +
* https://help.ubuntu.com/14.04/serverguide/dns-configuration.html
 +
 +
* http://blog.bobbyallen.me/2013/09/19/setting-up-internal-dns-on-ubuntu-server-12-04-lts/
 +
 +
* http://doc.ubuntu-fr.org/bind9  (in French)
 +
 +
 +
Bug fixes:
 +
 +
* no forwarding due to DNS-SEC errors (broken trust chain): http://pewetheb.blogspot.se/2013/11/named-error-broken-trust-chain.html

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: