350-401 Python for Network Automation Practice Test 2 — 15 Questions

Question 1

A network engineer writes a Python script using Paramiko to execute a command on a Cisco IOS device:

```python
import paramiko

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect('192.168.1.1', username='admin', password='cisco123')
stdin, stdout, stderr = ssh.exec_command('show version')
output = stdout.read().decode()
print(output)
ssh.close()
```

What is a potential issue with this approach?

Accepted Answer

The script will fail because Cisco IOS does not support SSH command execution; it requires an interactive shell session.. Paramiko's exec_command() is designed for SSH command execution, but Cisco IOS devices do not support direct command execution via SSH like Unix systems. Instead, the device expects an interactive shell. The command may not execute or may return an error because the SSH channel is not a shell. Netmiko or similar libraries handle this by opening a shell and sending commands.

Answer

The script will work fine because exec_command() sends the command over SSH.

Answer

The script will fail because the username and password are passed as plaintext; Paramiko requires key-based authentication.

Answer

The script will fail because the output should be read using stdout.readlines() instead of stdout.read().

Question 2

A network engineer uses the Requests library to send a RESTCONF PATCH request to modify the hostname of a Cisco IOS-XE device:

```python
import requests
from requests.auth import HTTPBasicAuth

url = 'https://192.168.1.1/restconf/data/Cisco-IOS-XE-native:native/hostname'
headers = {'Content-Type': 'application/yang-data+json'}
auth = HTTPBasicAuth('admin', 'cisco123')
payload = {
    'Cisco-IOS-XE-native:hostname': 'NewRouter'
}
response = requests.patch(url, json=payload, headers=headers, auth=auth, verify=False)
print(response.status_code)
```

What is the expected HTTP status code if the request is successful?

Accepted Answer

204 No Content. In RESTCONF, a successful PATCH request returns 204 No Content, as the resource is modified and no content is returned in the response body. Some implementations may return 200, but the standard is 204.

Answer

200 OK

Answer

201 Created

Answer

202 Accepted

Question 3

A network engineer writes an Ansible playbook to gather facts from a Cisco IOS device using the ios_facts module:

```yaml
---
- name: Gather IOS Facts
  hosts: ios_devices
  gather_facts: no
  tasks:
    - name: Collect facts
      cisco.ios.ios_facts:
        gather_subset:
          - hardware
      register: device_facts

- name: Show serial number
      debug:
        msg: "Serial number is {{ device_facts['ansible_facts']['ansible_net_serialnum'] }}"
```

What is a potential issue with this playbook?

Accepted Answer

The playbook is missing 'connection: network_cli' and 'become: yes' to enable network device access.. The playbook uses 'gather_facts: no' at the play level, which is fine. However, the ios_facts module returns facts under the key 'ansible_facts' by default, but the registered variable 'device_facts' will contain the entire response, including 'ansible_facts' as a subkey. The debug message tries to access 'device_facts['ansible_facts']['ansible_net_serialnum']', which is correct. But there is a subtle issue: The module 'ios_facts' requires the connection to be 'network_cli' and privilege escalation. If not set, the task may fail. Also, the 'gather_subset' parameter is misspelled as 'gather_subset' instead of 'gather_subset'? Actually, it's 'gather_subset' in the module. Wait, the correct parameter is 'gather_subset'? Let me check: In cisco.ios.ios_facts, the parameter is 'gather_subset' (with underscore). The playbook uses 'gather_subset' which is correct. Hmm. Another common issue: The 'ansible_net_serialnum' fact might not be available if the hardware subset does not include it. But hardware subset does include serial number. The real issue might be that the playbook does not specify 'connection: network_cli' and 'become: yes', which are required for network modules. That is the most likely problem.

Answer

The 'gather_subset' parameter is misspelled; it should be 'gather_subset' (correct spelling).

Answer

The registered variable 'device_facts' should be accessed as 'device_facts.ansible_facts.ansible_net_serialnum' using dot notation.

Answer

The 'hardware' subset is invalid; it should be 'all' to get serial number.

Question 4

Examine the following Python script snippet that uses netmiko to configure a Cisco IOS-XE device:

```python
from netmiko import ConnectHandler

device = {
    'device_type': 'cisco_ios',
    'ip': '192.168.1.1',
    'username': 'admin',
    'password': 'cisco',
}

connection = ConnectHandler(**device)
output = connection.send_command('show ip interface brief')
print(output)
connection.disconnect()
```

What is the primary purpose of this script?

Accepted Answer

It retrieves and prints the output of 'show ip interface brief'.. The script uses netmiko to connect to a Cisco device and retrieve the output of 'show ip interface brief'.

Answer

It configures an IP address on an interface.

Answer

It saves the running configuration to startup configuration.

Answer

It backs up the configuration to a TFTP server.

Question 5

Consider the following Python script using the requests library to interact with a Cisco IOS-XE device via RESTCONF:

```python
import requests
from requests.auth import HTTPBasicAuth

url = 'https://192.168.1.1/restconf/data/Cisco-IOS-XE-native:native/interface/GigabitEthernet=1/0/1'
headers = {
    'Accept': 'application/yang-data+json',
    'Content-Type': 'application/yang-data+json'
}
auth = HTTPBasicAuth('admin', 'cisco')

response = requests.get(url, headers=headers, auth=auth, verify=False)
print(response.json())
```

What is the script attempting to do?

Accepted Answer

It retrieves the configuration of GigabitEthernet1/0/1 in JSON format.. The script sends a GET request to retrieve the configuration of GigabitEthernet1/0/1 using RESTCONF.

Answer

It updates the IP address of GigabitEthernet1/0/1.

Answer

It deletes the interface configuration.

Answer

It creates a new interface.

Question 6

Examine this Python script that uses the napalm library to manage a Cisco IOS-XE device:

```python
from napalm import get_network_driver
driver = get_network_driver('ios')
device = driver('192.168.1.1', 'admin', 'cisco')
device.open()
print(device.get_facts())
device.close()
```

What is the output of this script?

Accepted Answer

It prints a dictionary containing device facts like hostname, model, uptime, etc.. The script uses NAPALM to retrieve device facts such as hostname, OS version, serial number, etc.

Answer

It displays the running configuration of the device.

Answer

It applies a configuration change to the device.

Answer

It tests connectivity to the device using ICMP.

Question 7

Review the following Python script that uses the Cisco IOS-XE RESTCONF API to modify an interface:

```python
import requests
from requests.auth import HTTPBasicAuth

url = 'https://192.168.1.1/restconf/data/Cisco-IOS-XE-native:native/interface/GigabitEthernet=1/0/1'
headers = {
    'Accept': 'application/yang-data+json',
    'Content-Type': 'application/yang-data+json'
}
auth = HTTPBasicAuth('admin', 'cisco')

payload = {
    'Cisco-IOS-XE-native:GigabitEthernet': {
        'name': '1/0/1',
        'description': 'Configured via RESTCONF'
    }
}

response = requests.put(url, headers=headers, auth=auth, json=payload, verify=False)
print(response.status_code)
```

What is the expected result if the script runs successfully?

Accepted Answer

It will set the description of GigabitEthernet1/0/1 to 'Configured via RESTCONF'.. A PUT request to the interface URL with a payload that includes a description will update the interface description.

Answer

It will create a new interface named GigabitEthernet1/0/1.

Answer

It will delete the interface configuration.

Answer

It will return an error because the payload is missing required fields.

Question 8

Examine the following Python script that uses the netmiko library to send configuration commands to a Cisco IOS-XE device:

```python
from netmiko import ConnectHandler

device = {
    'device_type': 'cisco_ios',
    'ip': '192.168.1.1',
    'username': 'admin',
    'password': 'cisco',
}

connection = ConnectHandler(**device)
config_commands = [
    'interface GigabitEthernet1/0/1',
    'description Link to Core',
    'ip address 10.1.1.1 255.255.255.0',
    'no shutdown'
]
output = connection.send_config_set(config_commands)
print(output)
connection.disconnect()
```

What is the purpose of this script?

Accepted Answer

It configures interface GigabitEthernet1/0/1 with a description, IP address, and enables it.. The script sends configuration commands to configure an interface with a description, IP address, and enable it.

Answer

It retrieves the running configuration of the device.

Answer

It saves the configuration to the startup configuration.

Answer

It tests connectivity to the device using ping.

Question 9

Consider the following Python script that uses the requests library to delete a VLAN via RESTCONF on a Cisco IOS-XE device:

```python
import requests
from requests.auth import HTTPBasicAuth

url = 'https://192.168.1.1/restconf/data/Cisco-IOS-XE-native:native/vlan=10'
headers = {
    'Accept': 'application/yang-data+json',
    'Content-Type': 'application/yang-data+json'
}
auth = HTTPBasicAuth('admin', 'cisco')

response = requests.delete(url, headers=headers, auth=auth, verify=False)
print(response.status_code)
```

What is the expected outcome if the VLAN 10 exists?

Accepted Answer

It will delete VLAN 10 from the device configuration.. A DELETE request to the VLAN resource will remove VLAN 10 from the device configuration.

Answer

It will retrieve the configuration of VLAN 10.

Answer

It will create VLAN 10 if it does not exist.

Answer

It will return an error because the payload is missing.

Question 10

What is the default OSPF hello interval on an Ethernet link?

Accepted Answer

10 seconds. OSPF uses a default hello interval of 10 seconds on broadcast and point-to-point links like Ethernet.

Answer

5 seconds

Answer

30 seconds

Answer

40 seconds

Question 11

Which BGP attribute is preferred when it has the lowest value?

Accepted Answer

MED (Multi-Exit Discriminator). BGP uses the MED (Multi-Exit Discriminator) attribute to influence inbound traffic; lower MED is preferred.

Answer

Local Preference

Answer

Weight

Answer

AS Path

Question 12

What is the maximum hop count for EIGRP?

Accepted Answer

100. EIGRP has a default maximum hop count of 100, but it can be configured up to 255.

Answer

15

Answer

255

Answer

Unlimited

Question 13

Drag and drop the steps of connecting to a network device via Netmiko into the correct order, from first to last.

Accepted Answer

Import netmiko library. The correct order starts with importing the Netmiko library, then creating a device dictionary with connection parameters, establishing the SSH connection using ConnectHandler, sending a command (e.g., 'show ip interface brief'), and finally closing the connection with disconnect(). This sequence follows standard Netmiko workflow for device access.

Question 14

Drag and drop the steps of parsing 'show interfaces' output using TextFSM into the correct order, from first to last.

Accepted Answer

Capture CLI output from device. First, the raw CLI output is captured from the device. Then, the TextFSM template file is loaded. The TextFSM parser is initialized with the template. The parsed data is extracted using the ParseText method. Finally, the structured data (list of dictionaries) is accessed for further processing.

Question 15

Drag and drop the steps of using a Python REST API call to retrieve device configuration via Cisco DNA Center into the correct order, from first to last.

Accepted Answer

Authenticate to DNA Center API and get token. The process begins with authenticating to the DNA Center API to obtain a token. Then, the device UUID is retrieved using a GET request to the device list endpoint. Next, a GET request is sent to fetch the running configuration for that device. The JSON response is parsed to extract the configuration text. Finally, the configuration is saved to a local file.