Junos Network

Juniper JunOS Network Automation

MCP Server

Device Inventory

Devices are defined in a devices.json file (not environment variables):

{
  "core-rtr-01": {
    "ip": "10.0.0.1",
    "port": 22,
    "username": "netops",
    "auth": {
      "type": "ssh_key",
      "private_key_path": "/home/user/.ssh/junos_key"
    }
  },
  "edge-rtr-02": {
    "ip": "10.0.0.2",
    "port": 22,
    "username": "admin",
    "auth": {
      "type": "password",
      "password": "changeme"
    }
  }
}

SSH key authentication is strongly recommended for production. Jumphost/ProxyCommand is supported via ssh_config field.

Environment Variables

Tools (10)

Device Inventory (3 tools)

CLI Execution (2 tools)

Configuration Management (3 tools)

Template & Facts (2 tools)

Safety Features

Command Blocklist (block.cmd)

The server ships with a blocklist that prevents destructive CLI commands:

• request system reboot
• request system halt
• request system power-cycle
• request system power-off
• request system zeroize

Custom patterns (regex) can be added to block.cmd.

Configuration Blocklist (block.cfg)

Prevents dangerous configuration changes:

• set system root-authentication — blocks root password changes
• set system login user ... authentication — blocks user credential changes

Custom patterns (regex) can be added to block.cfg.

Credential Filtering

get_router_list automatically strips passwords and SSH key paths before returning device data.

Workflows

1. JunOS Device Discovery

get_router_list → inventory all available Junos routers
→ gather_device_facts(router) per device → hostname, model, serial, version, uptime
→ Cross-reference with NetBox/Nautobot → flag discrepancies
→ GAIT

2. JunOS Health Check

get_router_list → identify target routers
→ execute_junos_command_batch(routers, "show chassis alarms") → alarm check
→ execute_junos_command_batch(routers, "show system processes extensive") → CPU/memory
→ execute_junos_command_batch(routers, "show interfaces terse") → interface status
→ execute_junos_command_batch(routers, "show bgp summary") → BGP peer health
→ Severity-sort findings → GAIT

3. JunOS Configuration Audit

get_router_list → select target routers
→ get_junos_config(router) → retrieve running config
→ junos_config_diff(router, version=1) → check for uncommitted or recent changes
→ Compare against golden config templates → flag deviations
→ GAIT

4. JunOS Configuration Deployment

ServiceNow CR must be in Implement state
→ get_junos_config(router) → baseline current config
→ render_and_apply_j2_template(template, vars, router, dry_run=true) → preview changes
→ render_and_apply_j2_template(template, vars, router, apply_config=true, commit_comment="CR-12345") → apply
→ get_junos_config(router) → verify post-change config
→ execute_junos_command(router, "show bgp summary") → verify protocol health
→ GAIT

5. JunOS Batch Operations

get_router_list → filter to target group (e.g., all edge routers)
→ execute_junos_command_batch(routers, "show version") → version inventory
→ execute_junos_command_batch(routers, "show ospf neighbor") → protocol health
→ Aggregate results → severity-sort → GAIT

6. JunOS Rollback Investigation

junos_config_diff(router, version=1) → compare against last committed config
→ junos_config_diff(router, version=2) → compare against version before that
→ Identify what changed, when, and the impact
→ execute_junos_command(router, "show system commit") → commit history
→ GAIT

Integration with Other Skills

JunOS MCP vs pyATS MCP

Guardrails

• Always call get_router_list first — verify the target device exists before executing commands
• Always baseline before changes — call get_junos_config before any load_and_commit_config or template apply
• Use dry_run for templates — set dry_run=true on render_and_apply_j2_template to preview changes before committing
• Gate config changes — all load_and_commit_config and render_and_apply_j2_template(apply_config=true) calls must have a ServiceNow CR in Implement state
• Use batch for fleet ops — prefer execute_junos_command_batch over looping execute_junos_command for multi-router operations
• Set reasonable timeouts — default is 360s; reduce for simple show commands, increase for large config operations
• Include commit comments — always provide a commit_comment referencing the ServiceNow CR number
• Verify after config pushes — call get_junos_config and protocol-specific show commands after changes
• Respect the blocklists — block.cmd and block.cfg prevent destructive operations; do not bypass them
• Record in GAIT — every command, config push, batch operation, and template rendering must be logged