SSH Mode

SSH mode allows you to connect to network devices over the network using the SSH protocol. This is the most common connection method for managing switches, routers, firewalls, and servers.

Prerequisites

• The target device has SSH enabled
• The probe has network connectivity to the device's management IP
• Valid SSH credentials (username/password or SSH key)
• The device's SSH port is reachable (default: 22)

Setting Up an SSH Connection

Step 1: Add the Device

1. Navigate to CMod > Devices
2. Click Add Device
3. Fill in the connection details:

Field	Description	Example
Name	Friendly device name	Core-SW-01
IP Address	Management IP	192.168.1.1
Port	SSH port	22
Device Type	Vendor/OS	Cisco IOS
Username	SSH username	admin
Authentication	Password or SSH Key	Password
Password	SSH password	(encrypted)

4. Click Save & Test

Step 2: Test Connectivity

When you click Save & Test, CMod will:

1. Attempt a TCP connection to the specified IP and port
2. Perform SSH key exchange
3. Authenticate with the provided credentials
4. Execute a basic command (e.g., show version) to verify the session works
5. Display the result and mark the device as "Connected" or report an error

Step 3: Open Terminal

1. Click the device in the CMod device list
2. Click Terminal
3. An interactive SSH terminal opens in your browser via WebSocket
4. You can type commands as if you were connected directly to the device

SSH Key Authentication

For key-based authentication:

1. When adding a device, select SSH Key as the authentication method
2. Paste your private key (PEM format) into the key field
3. Optionally provide a key passphrase
4. The public key must already be installed on the target device

tip

SSH key authentication is more secure and recommended for production environments. It also enables unattended operations like scheduled configuration backups.

Connection Settings

Timeout Configuration

Setting	Default	Range
Connection timeout	10 seconds	5-60 seconds
Command timeout	30 seconds	10-300 seconds
Idle timeout	15 minutes	5-60 minutes
Keep-alive interval	30 seconds	10-120 seconds

Configure these under CMod > Settings > SSH.

SSH Options

Option	Default	Description
Strict host key checking	Disabled	Verify the device's SSH host key
Preferred ciphers	Auto	Override the cipher negotiation order
Terminal type	xterm-256color	Terminal emulation type
Terminal size	80x24	Columns x Rows

Running Commands

Interactive Terminal

The WebSocket terminal provides a real-time interactive session:

• Full ANSI color support
• Tab completion (passed through to the device)
• Command history (up/down arrows)
• Copy/paste support
• Session recording (optional)

Command Templates

Execute predefined command sequences:

1. Select the device
2. Click Run Template
3. Choose a template
4. If the template has variables, fill in the values
5. Click Execute

Example template with variables:

configure terminal
interface {{interface}}
description {{description}}
switchport mode access
switchport access vlan {{vlan_id}}
no shutdown
end
write memory

Bulk Execution

Run the same command or template across multiple devices:

1. Navigate to CMod > Bulk Operations
2. Select target devices (checkboxes)
3. Choose a template or enter a command
4. Click Execute on Selected
5. Results are displayed per device in a tabbed view

Configuration Backup via SSH

CMod can automatically back up device configurations:

1. Navigate to CMod > Backup Schedule
2. Click Add Schedule
3. Select the devices to back up
4. Set the schedule (daily, weekly, or custom cron)
5. Choose the backup command template (e.g., "Show Running Config")
6. Click Save

Backed-up configurations are stored on the probe and include:

• Timestamp
• Device hostname
• Configuration diff from previous backup
• Full configuration text

Troubleshooting

Connection refused

• Verify SSH is enabled on the target device
• Confirm the IP address and port are correct
• Check that no firewall is blocking the connection between the probe and device

Authentication failed

• Verify the username and password/key are correct
• Some devices lock out after multiple failed attempts; wait and try again
• Check if the device requires a specific SSH protocol version (SSHv2)

Terminal hangs or is unresponsive

• The device may be waiting for a command to complete; press Ctrl+C
• Check the command timeout setting
• Verify the keep-alive interval is configured

Commands produce unexpected output

• Ensure the correct device type is selected; different vendors use different command syntax
• Some commands require elevated privilege mode (e.g., enable on Cisco)

FAQ

Q: Can I use SSH jump hosts / bastion hosts? A: Not currently. CMod connects directly from the probe to the target device. Ensure the probe has routing to all managed devices.

Q: Are SSH sessions logged? A: Yes. All commands executed through CMod are logged in the audit trail with the username, timestamp, device, and command text.

Q: Can I upload files to a device via SSH? A: SCP/SFTP file transfer is planned for a future release. Currently, CMod supports command-line interaction only.

For additional help, contact support@netreconapp.com.