{"id":4648,"library":"netmiko","title":"Netmiko","description":"Netmiko is a multi-vendor Python library designed to simplify the process of establishing and managing CLI connections to network devices via SSH, Telnet, or Serial. It handles common networking tasks like sending commands, entering/exiting configuration modes, and transferring files. As of version 4.6.0, Netmiko is actively maintained, frequently adding new device drivers and enhancing existing functionality.","status":"active","version":"4.6.0","language":"en","source_language":"en","source_url":"https://github.com/ktbyers/netmiko","tags":["network","cli","ssh","automation","multi-vendor","telnet","serial"],"install":[{"cmd":"pip install netmiko","lang":"bash","label":"Install Netmiko"}],"dependencies":[{"reason":"SSH client library for secure shell connections.","package":"paramiko"},{"reason":"Serial port backend for console connections.","package":"pyserial"},{"reason":"SCP client for secure file transfers.","package":"scp"},{"reason":"Collection of TextFSM templates for parsing structured output from network devices.","package":"ntc-templates"}],"imports":[{"symbol":"ConnectHandler","correct":"from netmiko import ConnectHandler"},{"note":"The exceptions module was moved in Netmiko 4.0.0.","wrong":"from netmiko.ssh_exceptions import NetmikoTimeoutException","symbol":"NetmikoTimeoutException","correct":"from netmiko.exceptions import NetmikoTimeoutException"},{"note":"The exceptions module was moved in Netmiko 4.0.0.","wrong":"from netmiko.ssh_exceptions import NetmikoAuthenticationException","symbol":"NetmikoAuthenticationException","correct":"from netmiko.exceptions import NetmikoAuthenticationException"}],"quickstart":{"code":"import os\nfrom netmiko import ConnectHandler\nfrom netmiko.exceptions import NetmikoTimeoutException, NetmikoAuthenticationException\n\n# Define device parameters using environment variables for security\ndevice_ip = os.environ.get('NETMIKO_HOST', 'your_device_ip')\nusername = os.environ.get('NETMIKO_USERNAME', 'your_username')\npassword = os.environ.get('NETMIKO_PASSWORD', 'your_password')\ndevice_type = os.environ.get('NETMIKO_DEVICE_TYPE', 'cisco_ios') # e.g., cisco_ios, juniper, arista_eos, etc.\n\nif 'your_device_ip' in device_ip or not all([device_ip, username, password, device_type]):\n    print(\"Please set NETMIKO_HOST, NETMIKO_USERNAME, NETMIKO_PASSWORD, and NETMIKO_DEVICE_TYPE environment variables, or update the placeholder values.\")\n    exit(1)\n\ndevice = {\n    \"device_type\": device_type,\n    \"host\": device_ip,\n    \"username\": username,\n    \"password\": password,\n    # \"optional_args\": {\"port\": 22}, # Example for custom SSH port\n}\n\ntry:\n    print(f\"Connecting to {device_ip}...\")\n    with ConnectHandler(**device) as net_connect:\n        print(\"Successfully connected!\")\n        # Use use_textfsm=True to attempt structured output parsing\n        output = net_connect.send_command(\"show ip int brief\", use_textfsm=True)\n        print(\"\\n--- Output of 'show ip int brief' (parsed with TextFSM) ---\\n\")\n        print(output)\n\n        # Example for sending configuration commands\n        # config_commands = [\"interface loopback 0\", \"ip address 1.1.1.1 255.255.255.255\"]\n        # output_config = net_connect.send_config_set(config_commands)\n        # print(\"\\n--- Configuration Output ---\\n\")\n        # print(output_config)\n\n        net_connect.disconnect()\n        print(\"Disconnected.\")\n\nexcept NetmikoAuthenticationException:\n    print(\"Authentication failed. Check username and password.\")\nexcept NetmikoTimeoutException:\n    print(\"Connection timed out. Check host IP and network connectivity.\")\nexcept Exception as e:\n    print(f\"An unexpected error occurred: {e}\")","lang":"python","description":"Connects to a network device using credentials from environment variables, sends a 'show ip int brief' command, and attempts to parse the output using TextFSM via `use_textfsm=True`. Remember to configure environment variables like NETMIKO_HOST, NETMIKO_USERNAME, NETMIKO_PASSWORD, and NETMIKO_DEVICE_TYPE before running."},"warnings":[{"fix":"Update import statements from `from netmiko.ssh_exceptions import ...` to `from netmiko.exceptions import ...`.","message":"The exceptions module was relocated from `netmiko.ssh_exceptions` to `netmiko.exceptions`. Code relying on the old import path will break.","severity":"breaking","affected_versions":"4.0.0 and later"},{"fix":"Review code using `send_command` or `send_command_timing` and adjust `read_timeout` parameters as needed, understanding its direct impact on how long Netmiko waits for output. `delay_factor` is still available but `read_timeout` is preferred.","message":"`send_command` and `send_command_timing` methods were refactored to primarily use the `read_timeout` argument. Older `delay_factor` based logic might behave differently, potentially causing unexpected timeouts or delays.","severity":"breaking","affected_versions":"4.0.0 and later"},{"fix":"Ensure your Python environment is running version 3.9 or higher to use Netmiko 4.6.0+.","message":"Support for older Python versions is periodically dropped. Python 3.7 support was dropped in v4.3.0, and Python 3.8 support was dropped in v4.5.0. Netmiko 4.6.0 requires Python >= 3.9.","severity":"breaking","affected_versions":"4.3.0, 4.5.0 and later"},{"fix":"When calling `send_command`, add `use_textfsm=True` to automatically parse output using available NTC templates. Example: `net_connect.send_command('show ip int brief', use_textfsm=True)`.","message":"While Netmiko includes `ntc-templates` (which uses `TextFSM`) for parsing, users often forget to enable structured output. By default, `send_command` returns raw string output. To get structured data for supported commands, you must use the `use_textfsm=True` argument.","severity":"gotcha","affected_versions":"All versions"},{"fix":"Carefully review `session_log` files for sensitive data before sharing. Consider limiting its use or implementing stricter log management practices like secure storage and access controls.","message":"The `session_log` functionality, while intended to hide sensitive information like passwords, has had scenarios where it failed to do so. It should always be treated as a security-sensitive file and carefully managed.","severity":"gotcha","affected_versions":"All versions, specifically addressed in 4.3.0 but remains a caution"},{"fix":"Upgrade Netmiko to version 4.4.0 or newer if using Python 3.13 and requiring Telnet functionality.","message":"Python 3.13 removed `telnetlib` from its standard library. Netmiko v4.4.0 vendorized `telnetlib` internally to maintain Telnet support. Users on older Netmiko versions (prior to 4.4.0) attempting to use Telnet with Python 3.13 would encounter import errors.","severity":"gotcha","affected_versions":"3.x to 4.3.x when used with Python 3.13"}],"env_vars":null,"last_verified":"2026-04-12T00:00:00.000Z","next_check":"2026-07-11T00:00:00.000Z"}