Backing up network device configurations is one of the most critical tasks in network administration. A missed backup could mean hours of manual reconfiguration after a failure. In this post, we will walk through a Python script that automates this process by connecting to a router or switch via SSH and saving the running-config to a local file.
We will use Netmiko, a popular Python library that simplifies SSH connections to network devices. Whether you manage a handful of switches or hundreds of routers, this script gives you a repeatable, automated way to capture configurations on demand.
Prerequisites
Before getting started, make sure you have:
- Python 3.8 or higher installed
- SSH access to your target network device
- Device credentials (username and password)
- The Netmiko library installed
To install Netmiko, run:
pip install netmiko
You can also clone the full project repository and install from the requirements file:
git clone https://github.com/NetworkThinkTank-Labs/backup-config-script.git
cd backup-config-script
pip install -r requirements.txt
Connecting to a Router or Switch
The core of our script uses Netmiko’s ConnectHandler to establish an SSH session. You provide the device type, hostname or IP address, and your credentials. Netmiko handles the SSH negotiation and drops you into an authenticated session.
Here is the connection function from our script:
def connect_to_device(host, username, password, device_type, port=22, enable_secret=None):
device = {
‘device_type’: device_type,
‘host’: host,
‘username’: username,
‘password’: password,
‘port’: port,
}
if enable_secret:
device[‘secret’] = enable_secret
connection = ConnectHandler(**device)
if enable_secret:
connection.enable()
return connection
Netmiko supports a wide range of device types including cisco_ios, cisco_nxos, arista_eos, and juniper_junos. You simply pass the appropriate device type string and Netmiko adapts its behavior accordingly.
Retrieving the Running Configuration
Once connected, pulling the running configuration is a single method call. We use send_command to execute show running-config on the device and capture the output as a string:
def backup_running_config(connection):
running_config = connection.send_command(‘show running-config’)
return running_config
Netmiko handles paging automatically, so even if your configuration is long, you will get the complete output without needing to send space or press Enter to page through it.
Saving the Configuration to a File
With the configuration captured in memory, the next step is writing it to a file. Our script creates a backups directory automatically and saves each configuration with a timestamped filename so you never overwrite a previous backup:
def save_config_to_file(config, hostname, output_dir=’backups’):
os.makedirs(output_dir, exist_ok=True)
timestamp = datetime.now().strftime(‘%Y-%m-%d_%H-%M-%S’)
safe_hostname = hostname.replace(‘.’, ‘‘).replace(‘:’, ‘‘)
filename = f'{safe_hostname}running-config{timestamp}.txt’
filepath = os.path.join(output_dir, filename)
with open(filepath, ‘w’) as f:
f.write(config)
return filepath
This produces backup files like:
backups/192_168_1_1_running-config_2026-04-10_14-30-00.txt
Running the Script
The script accepts command-line arguments so you can target any device without editing the code:
python backup_config.py –host 192.168.1.1 –username admin –password mypassword
You can also specify a different device type, SSH port, output directory, or enable password:
python backup_config.py –host 10.0.0.1 –username admin –password mypassword –device-type cisco_nxos –output-dir /var/backups/network
When you run the script, you will see output like this:
[] Connecting to 192.168.1.1:22 (cisco_ios)… [+] Successfully connected to 192.168.1.1 [] Retrieving running-config…
[+] Retrieved 15234 characters of configuration
[+] Configuration saved to backups/192_168_1_1_running-config_2026-04-10_14-30-00.txt
[+] Disconnected. Backup complete!
What is Next
This script provides a solid foundation for network configuration backups. Here are some ideas for extending it:
- Loop through a list of devices from a CSV or YAML inventory file to back up your entire network in one run
- Schedule the script with cron (Linux) or Task Scheduler (Windows) for automatic daily backups
- Add email or webhook notifications on success or failure
- Compare configurations between backups to detect unauthorized changes using difflib
- Integrate with Git to version-control your configurations automatically
Wrapping Up
Automating network device backups does not have to be complicated. With Python and Netmiko, you can connect to any router or switch, pull the running configuration, and save it to a timestamped file in just a few lines of code.
Check out the full source code and setup instructions in the GitHub repository: https://github.com/NetworkThinkTank-Labs/backup-config-script
If you found this useful, check out my other posts on network automation including Monitoring IP SLAs with Python, DNA Center, and NetBox and Build a Home Lab Like a Pro. Stay tuned for more content from the NetworkThinkTank!
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