🔐 ssh-mcp-server

SSH-based MCP (Model Context Protocol) server that allows remote execution of SSH commands via the MCP protocol.

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📝 Project Overview

ssh-mcp-server is a bridging tool that enables AI assistants and other applications supporting the MCP protocol to execute remote SSH commands through a standardized interface. This allows AI assistants to safely operate remote servers, execute commands, and retrieve results without directly exposing SSH credentials to AI models.

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✨ Key Features

• 🔒 Secure Connections: Supports multiple secure SSH connection methods, including password authentication and private key authentication (with passphrase support)
• 🛡️ Command Security Control: Precisely control the range of allowed commands through flexible blacklist and whitelist mechanisms to prevent dangerous operations
• 🔄 Standardized Interface: Complies with MCP protocol specifications for seamless integration with AI assistants supporting the protocol
• 🚇 Dual Transport Modes: Supports both exec and shell transport modes for direct SSH hosts and bastion or jump-host scenarios
• 📂 File Transfer: Supports bidirectional file transfers, uploading local files to servers or downloading files from servers
• 🔑 Credential Isolation: SSH credentials are managed entirely locally and never exposed to AI models, enhancing security
• 🚀 Ready to Use: Can be run directly using NPX without global installation, making it convenient and quick to deploy

📦 Open Source Repository

GitHub: https://github.com/classfang/ssh-mcp-server

NPM: https://www.npmjs.com/package/@fangjunjie/ssh-mcp-server

🛠️ Tools List

Tool	Name	Description
execute-command	Command Execution Tool	Execute SSH commands on remote servers and get results
upload	File Upload Tool	Upload local files to specified locations on remote servers
download	File Download Tool	Download files from remote servers to local specified locations
list-servers	List Servers Tool	List all available SSH server configurations

📚 Usage

🔧 MCP Configuration Examples

⚠️ Important: In MCP configuration files, each command line argument and its value must be separate elements in the args array. Do NOT combine them with spaces. For example, use "--host", "192.168.1.1" instead of "--host 192.168.1.1".

⚙️ Command Line Options

Options:
  --config-file       JSON configuration file path (recommended for multiple servers)
  --ssh-config-file   SSH config file path (default: ~/.ssh/config)
  --ssh               SSH connection configuration (can be JSON string or legacy format)
  -h, --host          SSH server host address or alias from SSH config
  -p, --port          SSH server port
  -u, --username      SSH username
  -w, --password      SSH password
  -k, --privateKey    SSH private key file path
  -P, --passphrase    Private key passphrase (if any)
  -a, --agent         SSH agent socket path
  -W, --whitelist     Command whitelist, comma-separated regular expressions
  -B, --blacklist     Command blacklist, comma-separated regular expressions
  -s, --socksProxy    SOCKS proxy server address (e.g., socks://user:password@host:port)
  --allowed-local-paths Additional allowed local paths for upload/download, comma-separated
  --allowed-remote-paths Allowed remote (POSIX, absolute) paths for SFTP upload/download, comma-separated
  --transport-mode    SSH transport mode: exec or shell (default: exec)
  --shell-ready-timeout Shell readiness probe timeout in milliseconds (default: 10000)
  --pty               Allocate pseudo-tty for command execution (default: true)
  --pre-connect       Pre-connect to all configured SSH servers on startup

🚇 When To Use transportMode

transportMode defaults to exec.

• Use exec for regular Linux hosts that support standard SSH command execution.
• Use shell for bastion hosts, jump hosts, network devices, or environments where you must enter an interactive shell before commands work reliably.

Behavior differences:

• exec: supports execute-command, upload, and download
• shell: runs commands through a persistent shell session with an internal command queue, but does not support upload or download because SFTP is unavailable in this mode

Switch to shell when:

• SSH login succeeds but exec command execution fails
• The remote side requires shell startup scripts, banners, or environment initialization first
• The target effectively exposes only an interactive shell

Configuration:

• CLI: --transport-mode shell --shell-ready-timeout 15000
• JSON config: set transportMode to "shell" and optionally set shellReadyTimeoutMs
• JSON config only: use shellCommandTimeoutMs to override the default timeout for shell-backed commands

Example:

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "bastion.example.com",
        "--port", "22",
        "--username", "ops",
        "--password", "pwd123456",
        "--transport-mode", "shell",
        "--shell-ready-timeout", "15000"
      ]
    }
  }
}

🔑 Using Password

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "192.168.1.1",
        "--port", "22",
        "--username", "root",
        "--password", "pwd123456"
      ]
    }
  }
}

🔐 Using Private Key

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "192.168.1.1",
        "--port", "22",
        "--username", "root",
        "--privateKey", "~/.ssh/id_rsa"
      ]
    }
  }
}

🔏 Using Private Key with Passphrase

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "192.168.1.1",
        "--port", "22",
        "--username", "root",
        "--privateKey", "~/.ssh/id_rsa",
        "--passphrase", "pwd123456"
      ]
    }
  }
}

📋 Using ~/.ssh/config

You can use host aliases defined in your ~/.ssh/config file. The server will automatically read connection parameters from the SSH config:

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "myserver"
      ]
    }
  }
}

Assuming your ~/.ssh/config contains:

Host myserver
    HostName 192.168.1.1
    Port 22
    User root
    IdentityFile ~/.ssh/id_rsa

You can also specify a custom SSH config file path:

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "myserver",
        "--ssh-config-file", "/path/to/custom/ssh_config"
      ]
    }
  }
}

Note: Command-line parameters take precedence over SSH config values. For example, if you specify --port 2222, it will override the port from SSH config.

🌐 Using SOCKS Proxy

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "192.168.1.1",
        "--port", "22",
        "--username", "root",
        "--password", "pwd123456",
        "--socksProxy", "socks://username:password@proxy-host:proxy-port"
      ]
    }
  }
}

📝 Using Command Whitelist and Blacklist

Use the --whitelist and --blacklist parameters to restrict the range of executable commands. Multiple patterns are separated by commas. Each pattern is a regular expression used to match commands.

Example: Using Command Whitelist

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "192.168.1.1",
        "--port", "22",
        "--username", "root",
        "--password", "pwd123456",
        "--whitelist", "^ls( .*)?,^cat .*,^df.*"
      ]
    }
  }
}

Example: Using Command Blacklist

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--host", "192.168.1.1",
        "--port", "22",
        "--username", "root",
        "--password", "pwd123456",
        "--blacklist", "^rm .*,^shutdown.*,^reboot.*"
      ]
    }
  }
}

Note: If both whitelist and blacklist are specified, the system will first check whether the command is in the whitelist, and then check whether it is in the blacklist. The command must pass both checks to be executed.

🧩 Multi-SSH Connection Example

There are three ways to configure multiple SSH connections:

📄 Method 1: Using Config File (Recommended)

Create a JSON configuration file (e.g., ssh-config.json):

Array Format:

[
  {
    "name": "dev",
    "host": "1.2.3.4",
    "port": 22,
    "username": "alice",
    "password": "{abc=P100s0}",
    "socksProxy": "socks://127.0.0.1:10808"
  },
  {
    "name": "bastion",
    "host": "9.9.9.9",
    "port": 22,
    "username": "ops",
    "password": "pwd123456",
    "transportMode": "shell",
    "shellReadyTimeoutMs": 15000,
    "shellCommandTimeoutMs": 45000
  },
  {
    "name": "prod",
    "host": "5.6.7.8",
    "port": 22,
    "username": "bob",
    "password": "yyy",
    "socksProxy": "socks://127.0.0.1:10808"
  }
]

Object Format:

{
  "dev": {
    "host": "1.2.3.4",
    "port": 22,
    "username": "alice",
    "password": "{abc=P100s0}",
    "socksProxy": "socks://127.0.0.1:10808"
  },
  "bastion": {
    "host": "9.9.9.9",
    "port": 22,
    "username": "ops",
    "password": "pwd123456",
    "transportMode": "shell",
    "shellReadyTimeoutMs": 15000,
    "shellCommandTimeoutMs": 45000
  },
  "prod": {
    "host": "5.6.7.8",
    "port": 22,
    "username": "bob",
    "password": "yyy",
    "socksProxy": "socks://127.0.0.1:10808"
  }
}

Then use the --config-file parameter:

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--config-file", "ssh-config.json"
      ]
    }
  }
}

🔧 Method 2: Using JSON Format with --ssh Parameter

You can pass JSON-formatted configuration strings directly:

{
  "mcpServers": {
    "ssh-mcp-server": {
      "command": "npx",
      "args": [
        "-y",
        "@fangjunjie/ssh-mcp-server",
        "--ssh", "{\"name\":\"dev\",\"host\":\"1.2.3.4\",\"port\":22,\"username\":\"alice\",\"password\":\"{abc=P100s0}\",\"socksProxy\":\"socks://127.0.0.1:10808\"}",
        "--ssh", "{\"name\":\"bastion\",\"host\":\"9.9.9.9\",\"port\":22,\"username\":\"ops\",\"password\":\"pwd123456\",\"transportMode\":\"shell\",\"shellReadyTimeoutMs\":15000}",
        "--ssh", "{\"name\":\"prod\",\"host\":\"5.6.7.8\",\"port\":22,\"username\":\"bob\",\"password\":\"yyy\",\"socksProxy\":\"socks://127.0.0.1:10808\"}"
      ]
    }
  }
}

📝 Method 3: Legacy Comma-Separated Format (Backward Compatible)

For simple cases without special characters in passwords, you can still use the legacy format:

npx @fangjunjie/ssh-mcp-server \
  --ssh "name=dev,host=1.2.3.4,port=22,user=alice,password=xxx" \
  --ssh "name=prod,host=5.6.7.8,port=22,user=bob,password=yyy"

⚠️ Note: The legacy format may have issues with passwords containing special characters like =, ,, {, }. Use Method 1 or Method 2 for passwords with special characters.

In MCP tool calls, specify the connection name via the connectionName parameter. If omitted, the default connection is used.

Example (execute command on 'prod' connection):

{
  "tool": "execute-command",
  "params": {
    "cmdString": "ls -al",
    "connectionName": "prod"
  }
}

Example (execute command with timeout options):

{
  "tool": "execute-command",
  "params": {
    "cmdString": "ping -c 10 127.0.0.1",
    "connectionName": "prod",
    "timeout": 5000
  }
}

⏱️ Command Execution Timeout

The execute-command tool supports timeout options to prevent commands from hanging indefinitely:

• timeout: Command execution timeout in milliseconds (optional, default is 30000ms)
• In shell mode, you can also set shellCommandTimeoutMs per connection in the JSON config file
• Error responses include stable code, message, and retriable fields for easier agent-side handling

This is particularly useful for commands like ping, tail -f, or other long-running processes that might block execution.

🗂️ List All SSH Servers

You can use the MCP tool list-servers to get all available SSH server configurations:

Example call:

{
  "tool": "list-servers",
  "params": {}
}

Example response:

[
  { "name": "dev", "host": "1.2.3.4", "port": 22, "username": "alice" },
  { "name": "prod", "host": "5.6.7.8", "port": 22, "username": "bob" }
]

🛡️ Security Considerations

This server provides powerful capabilities to execute commands and transfer files on remote servers. To ensure it is used securely, please consider the following:

• Command Whitelisting: It is strongly recommended to use the --whitelist option to restrict the set of commands that can be executed. Without a whitelist, any command can be executed on the remote server, which can be a significant security risk.
• Private Key Security: The server reads the SSH private key into memory. Ensure that the machine running the ssh-mcp-server is secure. Do not expose the server to untrusted networks.
• Denial of Service (DoS): The server does not have built-in rate limiting. An attacker could potentially launch a DoS attack by flooding the server with connection requests or large file transfers. It is recommended to run the server behind a firewall or reverse proxy with rate-limiting capabilities.
• Path Traversal: The server has built-in protection against path traversal attacks on the local filesystem. However, it is still important to be mindful of the paths used in upload and download commands.
• Local Transfer Scope: By default, local file transfers are restricted to the current working directory. Use --allowed-local-paths or allowedLocalPaths in config only for explicitly trusted directories.
• Remote Transfer Scope: SFTP upload/download accepts only absolute POSIX paths. If allowedRemotePaths (or --allowed-remote-paths) is not configured, any remote path is accepted and the server prints a startup warning. Configure allowedRemotePaths to whitelist a small set of remote directories; this is strongly recommended to prevent prompt-injection-driven reads or writes of files like ~/.ssh/authorized_keys or /etc/sshd_config.

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