check_smb

Check SMB/CIFS file-sharing service reachability. Sends an SMB2 Negotiate request and verifies the response magic bytes. Port 445 = direct SMB, 139 = NetBIOS over TCP.

SERVERMcp Nettools SOURCEaaronckj/mcp-nettools

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/aaronckj-mcp-nettools/check-smb.md

WHAT IT DOES

What check_smb does on Mcp Nettools

AI agents call check_smb to retrieve information from Mcp Nettools without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why check_smb is rated Low

The tool interrogates network services to determine if SMB is running and responsive, similar to ping or port checking on the server (network diagnostics). It sends a protocol handshake request and analyzes the response—a read operation. No data is modified, deleted, or executed.

From the tool's definition Tool performs an SMB/CIFS service reachability check by 'sending an SMB2 Negotiate request and verifies the response magic bytes.' This is a probe or diagnostic query that reads service availability/metadata without modifying state, executing arbitrary code,…

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs check_smb safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Nettools, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For check_smb, this is the rule to start with:

check_smb Allowed

check_smb is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "check_smb": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Nettools, apply this rule, and every check_smb call is checked against it from then on.

FAQ

Questions about check_smb

What does the check_smb tool do? +

Check SMB/CIFS file-sharing service reachability. Sends an SMB2 Negotiate request and verifies the response magic bytes. Port 445 = direct SMB, 139 = NetBIOS over TCP. It is categorised as a Read tool in the Mcp Nettools MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on check_smb? +

Register the Mcp Nettools MCP server in PolicyLayer and add a rule for check_smb: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Mcp Nettools. Nothing to install.

What risk level is check_smb? +

check_smb is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit check_smb? +

Yes. Add a rate_limit block to the check_smb rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block check_smb completely? +

Set action: deny in the PolicyLayer policy for check_smb. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides check_smb? +

check_smb is provided by the Mcp Nettools MCP server (aaronckj/mcp-nettools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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