smtp_check

Check an SMTP server: connectivity, banner, advertised capabilities, and STARTTLS support. port: 25 (SMTP), 465 (SMTPS/SSL), 587 (submission). check_starttls: attempt STARTTLS upgrade on port 25/587.

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/smtp-check.md

WHAT IT DOES

What smtp_check does on Mcp Nettools

AI agents call smtp_check 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 smtp_check is rated Low

This tool performs diagnostic/read-only checks against an SMTP server — it reads connectivity status, banner information, advertised capabilities, and STARTTLS support. It does not send emails, modify any data, or execute commands with side effects. It is purely an inspection/query tool.

From the tool's definition Check an SMTP server: connectivity, banner, advertised capabilities, and STARTTLS support

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs smtp_check 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 smtp_check, this is the rule to start with:

smtp_check Allowed

smtp_check 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": {
    "smtp_check": {}
  }
}

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 smtp_check call is checked against it from then on.

FAQ

Questions about smtp_check

What does the smtp_check tool do? +

Check an SMTP server: connectivity, banner, advertised capabilities, and STARTTLS support. port: 25 (SMTP), 465 (SMTPS/SSL), 587 (submission). check_starttls: attempt STARTTLS upgrade on port 25/587. 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 smtp_check? +

Register the Mcp Nettools MCP server in PolicyLayer and add a rule for smtp_check: 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 smtp_check? +

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

Can I rate-limit smtp_check? +

Yes. Add a rate_limit block to the smtp_check 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 smtp_check completely? +

Set action: deny in the PolicyLayer policy for smtp_check. 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 smtp_check? +

smtp_check 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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