# SAE R3.06 Report : network architecture : DNS
#### Group : Maël Jansen / Yahn Bervas

1. [IP configiration for the machines](#IP-configuration-for-the-machines)
2. [Local naming configuration](#Local-naming-configuration)
3. [DNS configuration for the client machines](#DNS-configuration-for-the-client-machines)
4. [DNS servers configuration](#DNS-servers-configuration)
4.1. [Primary server configuration](#Primary-server-configuration)
4.2. [Secondary server configuration](#Secondary-server-configuration)
4.3. [Etude of the LAN server](#Etude-of-the-LAN-server)
4.4. [Principal domain configuration](#Principal-domain-configuration)
4.5. [Reversed zone configuration](#Reversed-zone-configuration)
4.6. [Sub domain configuration](#Sub-domain-configuration)

### IP configuration for the machines

To give an IP address with DHCP we need to edit the file : /etc/network/interfaces (on all machines) to add :

iface eth0 inet dhcp

After doing a ifup to start the interfaces your machine will have their address :

dns2 => IP:192.168.0.2
client1 => IP:192.168.0.10
client2 => IP:192.168.0.20
dns1 => IP:192.168.0.1

You can test the communication between the machines with the command :

ping <IP>

And check the routes with the command :

route


### Local naming configuration

To localy associate a name with the IP you can write in the file : /etc/hosts (on dns1)

<IP> <name>
You can find a screenshot of the file below :

Now you can communicate between dns1 and the others machine with their name :

ping <name>

### DNS configuration for the client machines

To configure the client machines you need to add a rule in the file : /etc/dhcp/dhclient.conf

For dns1 and dns2 you need to add :

supersede domain-name-servers 127.0.0.1
For client1 :

supersede domain-name-servers <IP dns1>

For client1 :

supersede domain-name-servers <IP dns2>
You can find an example screenshot for dns1 below :

To relay the DNS request we need to edit the file : /etc/bind/named.conf.options (on dns1 and dns2)

forwarders {
172.16.0.3;
}:

alow-query {
any;
};
### DNS servers configuration

#### Primary server configuration

To configure a new primary DNS zone we need to define it in the file : /etc/bind/named.conf.local

zone "netas" {
type master;
file "/etc/bind/db.netas";
};

To fill our DNS zone we need to copy the file : /etc/bind/dd.empty in the file that will just define :

cp /etc/bind/db.empty /etc/bind/db.netas

Now we can update the zone file : (/etc/bind/db.netas)

@ IN SOA dns1.netas. contact.netas. (
1 ;
604800
86400
2419200
86400 )

You need to add a new NS input that will be indicate the name of the principal DNS server (in the zone file too) :

@ IN NS dns1

You need to add an input A to specify the IP for dns1 :

dns1 IN A <IP dns1>

You can find an screeshot of the result below :

Now you can restart dns1 with the command :

systemctl restart named

__You need to increment the serial number after each modification of the db.netas file__

You can also do :

systemctl reload named
to reaload the configurations files without restart your dns1

If you want to check the status of your server you can do :

systemctl status named

The logs are stored in the file : /var/log/syslog
You can also see the complete log with :

journalctl --unit named

To test your configuration you can do a ping between client1 and dns1.netas

ping dns1.netas

Now you need to add an input A for dns2 just like hte one for dns1 (in the file : /etc/bind/db.netas on dns1)

Add to CNAME input to name the "dns-primaire" and "dns-secondaire" alias to the dns1 and dns2 servers (in the file : /etc/bind/db.netas on dns1)

dns-primaire IN CNAME dns1
dns-secondaire IN CNAME dns2

You can use the ping command between the client1 machine and "dns1.netas", "dns2.netas", "dns-primaire.netas" and "dns-secondaire.netas" as you can see below

Ping between client1 and dns1.netas

Ping between client1 and dns-primaire.netas

#### Secondary server configuration

In the configuration zone of dns1 you have to put a new input to identify dns2 as a server : (in the file : /etc/bind/db.netas on dns1)

@ IN NS dns2

On dns2 you need to declare the netas zone as secondary of the dns1 server (on the file : /etc/bind/named.conf.local)

zone "netas" {
type slave;
file "/var/lib/bind/db.netas";
masters { <IP du serveur dns1>; };
};

After restarting the dns1 and dns2 servers you can make a ping between client2 and the machines in the netas zone to verify if they can communicate :

example : ping dns1.netas

On the client machines you have to use the host command to check if the two server are in the nets zone :

host dns-primaire <IP de dns1>
host dns-primaire <IP de dns2>
host dns-secondaire <IP de dns1>
host dns-secondaire <IP de dns2>

You can find screenshots of the command performed on client1 below :


#### Etude of the LAN server

There is 22 fix bytes on the IP address because we have /22 on the mask.

You can scan the LAN server to collect IP address which composed the sub-net with the commmand :

map -T5 -sP 10.0.0.0/22


Now you have to connect in ssh with each collected IP to set up the connection between all of the machine which composed the LAN server

ssh <username>@<IP machine>

username : tc
password : plop

#### Principal domain configuration

You have to add a new input A for each web server (s1, s2, s3) in the file : /etc/bind/db.netas

@ IN NS s1
@ IN NS s2
@ IN NS s3

s1 IN A 10.0.2.1
s2 IN A 10.0.2.2
s3 IN A 10.0.2.3

You can add an CNAME input for each web server :

creative IN CNAME s1
grayscale IN CNAME s2
wonder IN CNAME s3

You can use ping or host commands if you want to test your alias a on the client1 and client2 machines.

Now you have to switch on graphic mod on the client1 machine.
Open your browser and test the enregistred site :

creative.netas
grayscale.netas
wonder.netas

You can find a screeshot of one of the sites below :


You can try it on client2 too.

#### Reversed zone configuration

You need to declare the reversed in the file : /etc/bind/named.conf.local (on dns1) :

zone "2.0.10.in-addr.arpa" {
type master;
file "/etc/bind/db.netas-rev";
};

And in the file : /etc/bind/db.netas-rev :

@ IN SOA dns1.netas. contact.netas (
1
604800
86400
2419200
86400 )

@ IN NS dns1.netas.
@ IN NS dns2.netas.
1 IN PTR s1.netas.
2 IN PTR s2.netas.
3 IN PTR s3.netas.

You can use ping and host commands to check your new configuration.

You have to declare dns2 to make it a second server for the reversed netas zone. You can check it with a ping and host too (on client2 this time).

#### Sub-domain configuration

You need to add a new NS input in the main netas zone : (in the file : /etc/bind/db.netas)

perf IN NS dns1

You have to declare this new sub-domain in the file : /etc/bind/named.conf.local :

zone "perf.netas" {
type master;
file "/etc/bind/db.perf.netas";
};

Create the associate file :

@ IN SOA dns1.perf.netas; contact.netas. (
1
604800
86400
2419200
86400 )
@ IN NS dns1
dns1 IN A <IP de dns1>

Complete the file to include the A inputs which pointing on p1 and p2.

Verify your configuration by using ping and host on client1.