Octet

Say this first

Netmiko is a Python library built on Paramiko that makes SSH to network devices easy. It knows each platform's prompts, disables paging, enters enable and config mode, and waits for output. You build a device dictionary with a device_type such as cisco_ios, open ConnectHandler, then call send_command for show commands and send_config_set for changes. It is screen scraping: reliable and universal, but you get text back unless you parse it.

Go deeper

A minimal script

Python

from netmiko import ConnectHandler

device = {
    "device_type": "cisco_ios",
    "host": "10.0.0.11",
    "username": "netops",
    "password": "secret",
    "secret": "enablepass",
}

with ConnectHandler(**device) as conn:
    conn.enable()
    print(conn.send_command("show ip interface brief"))
    output = conn.send_config_set([
        "interface Loopback100",
        "description mgmt-test",
    ])
    print(output)
    conn.save_config()

The methods you use most

Method	What it does
`send_command(cmd)`	Send one command, wait for the prompt, return the output
`send_command(cmd, use_textfsm=True)`	Parse the output with a TextFSM template into a list of dictionaries
`send_config_set(list)`	Enter config mode, send the lines, exit
`send_config_from_file(path)`	Same, from a file
`save_config()`	Platform-appropriate save (`write memory` on IOS)
`enable()`	Enter privileged mode using `secret`

Common device types

cisco_ios, cisco_xe, cisco_nxos, cisco_xr, arista_eos, juniper_junos, linux.

Timeouts

In Netmiko 4, send_command waits up to read_timeout (10 seconds by default) for the prompt. A big show running-config on a core switch can need read_timeout=60.

They will ask next

Netmiko or NAPALM or Nornir?
Netmiko is the SSH layer: any command on almost any platform. NAPALM adds a vendor-neutral API with structured getters and config replace or merge with diffs. Nornir is a Python framework that runs tasks (Netmiko, NAPALM, others) across an inventory in parallel. They are often used together.
How do you turn CLI output into data?
TextFSM templates (the ntc-templates collection ships hundreds) through use_textfsm=True, Cisco Genie parsers through use_genie=True, or TTP templates. Better still, ask for structured output where the platform offers it, such as | json on NX-OS and EOS or | display json on Junos.

Traps

Calling Netmiko an API. It types commands into an SSH session like a person would.
Parsing output with hand-written string splits that break on the next software release.

How did you do?