This repository documents a small lab where a simple python script is used to backup three cisco routers running in a PNETLabs enviroment. The aim of this repository is to showcase automation capabilities and document my personal experience with it.
- PNETLabs
- 3x Cisco routers
- Ubuntu VM
- Reachability between routers and Ubuntu VM
- SSH configuration on Routers and Ubuntu VM
- Netmiko installed
- CSV file for device info
Each router, has identical configuration for SSH
As I wanted to use SSH keys for passwordless authentication, I added the public key from the Ubuntu VM to each of the routers
Eigrp was used to exchange routes between the routers
Loop 0 was configured and used to reach the routers.
SSH keys were generated that would allow the script to use passwordless authentication
An environment variable was configured and added to .bashrc to store the username. This avoids hardcoding the username in the script or using the input() function.
I installed netmiko in a venv however, it can also be installed in the global python
A CSV was created containing the information for routers
- Created a python file with the following code:
- Ran the script on the Ubuntu VM and confirmed its success
- A lot of the things i have done in this lab can be done differently
- For example, you can use the input() and getpass() function for the SSH
- You can use a list for the routers instead of the CSV file
- The routers did not have enable secret password configured
- I just did it in this way as i wanted to experience if the routers were capble of Key based authentcation and how CSV files with python
- Alot of issues were encountured during this lab
- The Cisco routers only supported older legacy RSA keys, which caused issues with the Ubuntu VM because modern SSH does not allow these keys by default
- Fixed this by creating a custom ssh config file which allowed the older legacy keys for the specific routers
- Initially, I used 2048-bit RSA keys for the Ubuntu VM, but this caused compatibility issues with the routers. The problem was resolved by using 1024-bit keys
- Manual SSH from the terminal worked, but SSH via Netmiko initially failed
- Issue was fixed by adding the "passphrase" and "disabled_algorithms" keys in the dictionary