_             _____    _   _    _____ 
   /\             | |           |  __ \  | \ | |  / ____|
  /  \     _   _  | |_    ___   | |  | | |  \| | | (___  
 / /\ \   | | | | | __|  / _ \  | |  | | | . ` |  \___ \ 
/ ____ \  | |_| | | |_  | (_) | | |__| | | |\  |  ____) |
/_/    \_\  \__,_|  \__|  \___/  |_____/  |_| \_| |_____/ 
                                

The English_version.py or French_version.py script automates the configuration of a DNS server using Bind9 on an Ubuntu system. It creates the necessary zone files for forward and reverse DNS lookups, updates the Bind9 configuration, and restarts the Bind9 service to apply the changes. In this configuration example we will use as IP address 192.168.183.17 and as domain name integris.ptt

Before running the script, ensure that the following dependencies are installed on your system:

• Python 3.x: The script is written in Python and requires Python 3.x to run.
• Bind9: The DNS server software that will be configured.
• dnspython: A DNS toolkit for Python to handle DNS queries and responses.
• shutil module: This is included in the Python Standard Library and is used for file operations like copying files.
• os module: This is also included in the Python Standard Library and is used for interacting with the operating system.

1. Install Bind9

   sudo apt update
   sudo apt install bind9 bind9utils bind9-doc
   

2. Install dnspython

   pip install dnspython

3. Execution of the script English_version.py

 sudo chmod +x English_version.py
 python3 English_version.py

The English_version.py script is in your current directory. You have Python 3 installed on your system. You have the necessary permissions to execute the script (you may need to use sudo).

import os
from shutil import copyfile

The script defines the paths to the forward and reverse zone files and the Bind9 local configuration file.

zone_file_path = '/etc/bind/db.integris.ptt'
reverse_zone_file_path = '/etc/bind/db.192.168.183'
named_conf_local_path = '/etc/bind/named.conf.local'

The forward and reverse zone file contents are defined as multi-line strings. These strings specify the DNS records for the domain integris.ptt and its reverse lookup.

zone_file_content = f"""
$TTL    604800
@       IN      SOA     ns.integris.ptt. root.integris.ptt. (
                              2         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@       IN      NS      ns.integris.ptt.
ns      IN      A       192.168.183.17
www     IN      A       192.168.183.17  
@       IN      A       192.168.183.17
"""

reverse_zone_file_content = f"""
$TTL    604800
@       IN      SOA     ns.integris.ptt. root.integris.ptt. (
                              2         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@       IN      NS      ns.integris.ptt.
17.183.168.192.in-addr.arpa.  IN      PTR     www.integris.ptt.
"""

The script appends the new zone configurations to named.conf.local.

named_conf_local_content = f"""
zone "integris.ptt" {{
    type master;
    file "{zone_file_path}";
}};

zone "183.168.192.in-addr.arpa" {{
    type master;
    file "{reverse_zone_file_path}";
}};
"""

This function writes the defined content to the respective zone files and updates named.conf.local.

def create_zone_files():
    # Write the forward zone file
    with open(zone_file_path, 'w') as zone_file:
        zone_file.write(zone_file_content)
    # Write the reverse zone file
    with open(reverse_zone_file_path, 'w') as reverse_zone_file:
        reverse_zone_file.write(reverse_zone_file_content)
    # Append the zone configurations to named.conf.local
    with open(named_conf_local_path, 'a') as named_conf_local:
        named_conf_local.write(named_conf_local_content)

This function restarts the Bind9 service to apply the new configuration.

def restart_bind9():
    os.system('sudo systemctl restart bind9')

The main function backs up the original files (if they exist), creates the new zone files, restarts Bind9, and prints a success message.

def main():
    # Backup original files if they exist
    if os.path.exists(zone_file_path):
        copyfile(zone_file_path, f"{zone_file_path}.bak")
    if os.path.exists(reverse_zone_file_path):
        copyfile(reverse_zone_file_path, f"{reverse_zone_file_path}.bak")
    if os.path.exists(named_conf_local_path):
        copyfile(named_conf_local_path, f"{named_conf_local_path}.bak")

    # Create zone files and restart Bind9
    create_zone_files()
    restart_bind9()
    print("DNS configuration applied successfully.")

# Entry point of the script
if __name__ == "__main__":
    main()

To ensure your system uses the new DNS server for name resolution, you need to update the /etc/resolv.conf file to point to the local DNS server. Edit /etc/resolv.conf and add the following lines:

nameserver 192.168.183.17
search integris.ptt

After running the script, perform the following tests to ensure the DNS server is functioning correctly:

1. Check Forward DNS Lookup

   Use the dig command to verify that the domain integris.ptt resolves to the correct IP address.

   dig @192.168.183.17 integris.ptt

2. Check Reverse DNS Lookup

   Use the dig command to verify the reverse DNS lookup for the IP address 192.168.183.17.

   dig @192.168.183.17 -x 192.168.183.17

3. Ping the Domain

   Use the ping command to ensure that the domain integris.ptt is reachable.

   ping integris.ptt

4. Check DNS Server Status

   Ensure that the Bind9 service is running correctly.

   sudo /etc/init.d/named status
   sudo named-checkzone integris.ptt /etc/bind/db.integris.ptt
   sudo named-checkconf

5. DNS Server correctly installed

root@Ubuntu:/etc/bind# ping integris.ptt
PING integris.ptt (192.168.183.17) 56(84) bytes of data.
64 bytes from www.integris.ptt (192.168.183.17): icmp_seq=1 ttl=64 time=0.086 ms
64 bytes from www.integris.ptt (192.168.183.17): icmp_seq=2 ttl=64 time=0.034 ms
64 bytes from www.integris.ptt (192.168.183.17): icmp_seq=3 ttl=64 time=0.168 ms
64 bytes from www.integris.ptt (192.168.183.17): icmp_seq=4 ttl=64 time=0.177 ms
64 bytes from www.integris.ptt (192.168.183.17): icmp_seq=5 ttl=64 time=0.084 ms
^C
--- integris.ptt ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4056ms
rtt min/avg/max/mdev = 0.034/0.109/0.177/0.054 ms
root@Ubuntu:/etc/bind#

This script automates the configuration of a DNS server by creating and updating the necessary zone files and configurations, then restarting the Bind9 service. By following the above steps and performing the DNS tests, you can ensure that your DNS server is set up and functioning as expected.