Difference between revisions of "DNS server unique zone"
Line 355: | Line 355: | ||
− | Now you can try to ping a client: | + | Now you can try to ping the router and a client: |
<syntaxhighlight lang="bash"> | <syntaxhighlight lang="bash"> | ||
+ | ping cisco-router | ||
ping smartcard-prod-00 | ping smartcard-prod-00 | ||
</syntaxhighlight> | </syntaxhighlight> | ||
Line 379: | Line 380: | ||
+ | Now you can try to ping a website: | ||
− | + | <syntaxhighlight lang="bash"> | |
+ | ping tcl.fr | ||
+ | </syntaxhighlight> | ||
Revision as of 14:21, 3 June 2014
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.
You can learn how it works through a simple Google request.
Here, I will present the installation of:
- DNS primary server (= DNS for domain smartcards.local) using BIND9
- Local domain (.local)
You can re-use all this content for a web-site or public domain. Just replace smartcards.local by mywebsite.com.
Contents
Setup
apt-get install bind9 dnsutils bind9-doc
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.
The external DNS can either be your ISP's DNS or Google's servers.
!! Mind the order !! First DNS have a higher priority.
Edit configuration file:
vim /etc/bind/named.conf.options
Uncomment and adjust the file content
[...]
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;
};
[...]
Declare the new domain
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";
};
Domain configuration file
Create the domain 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 (you can use mywebsite.com)
;
$TTL 604800
@ IN SOA smartcard-gw.smartcards.local. root.smartcards.local. (
201406031132 ; Serial
; As the serial be changed everytime you edit this file
; it is recommended to use the pattern "yyyyMMddHHmm"
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
;
; -- alternative --
; To declare a server a specific domain only
;
;website.com IN NS smartcard-gw.website.com.
;website.com 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 172.16.50.10
smarcartd-prod-01 IN A 172.16.50.11
smarcartd-prod-02 IN A 172.16.50.12
smarcartd-prod-03 IN A 172.16.50.13
; 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 file
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. (
201406031301 ; Serial
; As the serial be changed everytime you edit this file
; it is recommended to use the pattern "yyyyMMddHHmm"
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
;
10 IN PTR smartcard-prod-00.smartcards.local.
11 IN PTR smartcard-prod-01.smartcards.local.
12 IN PTR smartcard-prod-02.smartcards.local.
13 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
Use the local DNS server as default one
Now that your server is ready to be used, you have to use it !!
- All the clients will get their configuration from DHCP (see DHCP server).
- On the local server, you have to edit your current IP settings
vim /etc/network/interfaces
Adjust it like that:
# The primary network interface [static IP]
auto eth0
iface eth0 inet static
address 172.16.50.2
netmask 255.255.255.0
gateway 172.16.50.1
network 172.16.50.0
broadcast 172.16.50.255
# Local DNS server on 172.16.50.2 as default. Then the DNS server itself will forward the requests to external DNS servers.
dns-nameservers 172.16.50.2
dns-search smartcards.local
dns-domain smartcards.local
Don't forget to reboot to take on your configuration changes !
Test your configuration
Test on SERVER side
Run the following commands to check your configuration. All commands should output OK or be a ping success. :)
Check the local zone:
named-checkzone smartcards.local /etc/bind/zones/smartcards.local
named-checkzone smartcards.local /etc/bind/zones/db.172
Check the reverse zone:
named-checkzone 50.16.172.in-addr.arpa. /etc/bind/db.172
Now you can try to ping the router and a client:
ping cisco-router
ping smartcard-prod-00
Now you can try to ping a website:
ping dev.daxiongmao.eu
Test on CLIENT side
Try to access ping the DNS server name from a client:
ping smartcard-gw
Now you can try to ping a website:
ping tcl.fr
Sources
You can find a lot of information about DNS on the web. I used the following tutorials:
- http://doc.ubuntu-fr.org/bind9 (in French)