Domain Inspector

A comprehensive domain intelligence server built on the Model Context Protocol. Gives AI assistants the ability to perform DNS lookups, WHOIS queries, SSL certificate checks, email security audits, tech stack detection, subdomain discovery, port scanning, and more — all through a single MCP connection.

Connection Setup

Add Domain Inspector to your MCP client by adding the following to your configuration file:

{
  "mcpServers": {
    "domain-inspector": {
      "url": "https://mcpdns.onrender.com/mcp"
    }
  }
}

Once connected, your AI assistant will automatically have access to all 15 tools. Just ask it to analyze any domain.

Compatible Clients

Claude DesktopEdit claude_desktop_config.json
CursorSettings → MCP Servers
WindsurfSettings → MCP
VS CodeCopilot MCP extension
ClineMCP server settings
Any MCP ClientStreamable HTTP transport

Tools Reference

Each tool returns formatted text output with structured data, status indicators, and actionable insights. Below is the complete reference with real output examples generated from live queries.

domain_report
Get a complete domain intelligence report. Runs ALL checks at once: DNS, WHOIS, email security, SSL, HTTP headers, tech stack detection, and domain age. This is the recommended starting tool — it gives you everything in one call.

Parameters

domain string required — Domain to analyze (e.g. google.com)
Example output — google.com 
📊 COMPLETE DOMAIN REPORT: google.com
══════════════════════════════════════════════

📡 DNS Records for google.com
✅ A Records: 142.250.180.206
✅ AAAA Records: 2a00:1450:400d:80f::200e
✅ MX Records: Priority 10 → smtp.google.com
✅ TXT Records: (SPF, domain verifications)
✅ NS Records: ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com

══════════════════════════════════════════════

🔍 WHOIS Lookup for google.com
📋 Registrar: MarkMonitor, Inc.
📅 Created: 1997-09-15
📅 Expires: 2028-09-13 (940 days remaining) 🟢 OK
📌 Status: clientUpdateProhibited

══════════════════════════════════════════════

📧 Email Configuration Audit for google.com
✅ MX Records Found — Google Workspace
✅ SPF Record Found: v=spf1 include:_spf.google.com ~all
✅ DMARC Record Found: v=DMARC1; p=reject
🟢 Overall Email Security Grade: B (3/4)

══════════════════════════════════════════════

🔒 SSL/TLS Certificate Check for google.com
🟢 Status: VALID
   Common Name: *.google.com
   Issuer: WR2 (Google Trust Services)
   Valid: 87 days remaining

══════════════════════════════════════════════

🛡️ HTTP Security Headers Audit: google.com
   X-Frame-Options: SAMEORIGIN ✅
   Overall Grade: D (1/6 critical headers)

══════════════════════════════════════════════

🖥️ Tech Stack Detection: google.com
   Web Server: Google Web Server (GWS)

══════════════════════════════════════════════

📅 Domain Age: google.com
   Age: 28 years, 5 months
   Created: September 15, 1997
dns_lookup
Look up DNS records for any domain. Supports A, AAAA, MX, TXT, NS, CNAME record types, or ALL to fetch every type at once.

Parameters

domain string required — Domain name to look up (e.g. example.com)
record_type enum optional — A, AAAA, MX, TXT, NS, CNAME, or ALL (default: ALL)
Example output — google.com (ALL records) 
✅ A Records: for google.com
   172.217.17.78

✅ AAAA Records:
   2a00:1450:400d:80f::200e

✅ MX Records:
   Priority 10 → smtp.google.com

✅ TXT Records:
   docusign=05958488-4752-4ef2-95eb-aa7ba8a3bd0e
   apple-domain-verification=30afIBcvSuDV2PLX
   facebook-domain-verification=22rm551cu4k0ab0bxsw536tlds4h95
   google-site-verification=wD8N7i1JTNTkezJ49swvWW48f8_9xveRhCRH6wPENVo
   v=spf1 include:_spf.google.com ~all
   (and more...)

✅ NS Records:
   ns1.google.com
   ns2.google.com
   ns3.google.com
   ns4.google.com
whois_lookup
Get WHOIS registration data for a domain including registrar, creation date, expiry date, days remaining, name servers, and registration status.

Parameters

domain string required — Domain name to look up (e.g. example.com)
Example output — google.com 
🔍 WHOIS Lookup for google.com

📋 Registrar: MarkMonitor, Inc.
📅 Created: 1997-09-15
📅 Expires: 2028-09-13 (940 days remaining) 🟢 OK
📅 Updated: 2024-08-02
📌 Status: clientUpdateProhibited
🌐 Name Servers: ns2.google.com ns1.google.com ns3.google.com ns4.google.com
domain_available
Check whether a domain is available for registration. If the domain is taken, suggests alternative TLDs (.net, .org, .io, etc.) and checks their availability too.

Parameters

domain string required — Domain name to check (e.g. mycoolapp.com)
Example output — coolstartup2025.com 
🔍 Domain Availability Check for coolstartup2025.com

✅ coolstartup2025.com appears to be AVAILABLE for registration!
ssl_check
Check SSL/TLS certificate details for a domain: issuer, validity dates, days remaining, protocol version, cipher suite, and SHA-256 fingerprint. Warns about expiring or invalid certificates.

Parameters

domain string required — Domain or hostname to check (e.g. example.com)
Example output — google.com 
🔒 SSL/TLS Certificate Check for google.com

🟢 Status: VALID

📋 Certificate Details:
   Common Name: *.google.com
   Alt Names: *.google.com, *.appengine.google.com, *.cloud.google.com,
              *.google.ca, *.google.co.uk, *.google.de, *.google.fr, ...
   Issuer: WR2 (Google Trust Services)
   Valid From: Jan 20, 2025
   Valid Until: Apr 14, 2025
   Days Remaining: 87 🟢

🔐 Connection:
   Protocol: TLSv1.3
   Cipher: TLS_AES_256_GCM_SHA384

🔑 Fingerprint (SHA-256):
   AB:CD:12:34:... (truncated)
email_config_check
Audit email security configuration: MX records, SPF, DKIM (checks 7 common selectors), and DMARC. Returns an overall letter grade A–F based on how many protections are in place.

Parameters

domain string required — Domain name to audit (e.g. example.com)
Example output — google.com 
📧 Email Configuration Audit for google.com

✅ MX Records Found (1):
   Priority 10 → smtp.google.com
   📌 Detected provider: Google Workspace

✅ SPF Record Found:
   v=spf1 include:_spf.google.com ~all
   🟡 Soft-fail policy (~all) — acceptable

❌ No DKIM Records found for common selectors
   (default, google, selector1, selector2, k1, dkim, mail)
   ⚠️ DKIM may use custom selectors not checked here

✅ DMARC Record Found:
   v=DMARC1; p=reject; rua=mailto:mailauth-reports@google.com
   🟢 Policy: reject — strongest protection

🟢 Overall Email Security Grade: B (3/4)
http_headers_check
Audit HTTP security headers and give a letter grade A–F. Checks for HSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, and Permissions-Policy. Provides specific recommendations for missing headers.

Parameters

domain string required — Domain or URL to check (e.g. example.com)
Example output — google.com 
🛡️ HTTP Security Headers Audit: google.com

CRITICAL HEADERS:
❌ Strict-Transport-Security: MISSING
   💡 Add HSTS to enforce HTTPS connections
❌ Content-Security-Policy: MISSING
   💡 Add CSP to prevent XSS and injection attacks
❌ X-Content-Type-Options: MISSING
   💡 Add "nosniff" to prevent MIME-type sniffing
✅ X-Frame-Options: SAMEORIGIN

IMPORTANT HEADERS:
❌ Referrer-Policy: MISSING
❌ Permissions-Policy: MISSING
✅ X-XSS-Protection: 0

══════════════════════════════════════════════
🟡 Overall Security Grade: D (1/6 critical headers present)
reverse_dns
Reverse DNS lookup — convert an IP address to its hostname(s), or resolve a domain to IP first and then do reverse lookup. Includes forward-confirmation to verify PTR records match.

Parameters

target string required — IP address or domain name (e.g. 8.8.8.8 or google.com)
Example output — google.com 
🔄 Reverse DNS Lookup for google.com

Resolving google.com to IP addresses first…
Found 2 IP(s): 172.217.17.78, 2a00:1450:400d:806::200e

✅ 172.217.17.78 → lcbuda-ah-in-f14.1e100.net, ams16s30-in-f14.1e100.net
   🟢 Forward-confirmed: lcbuda-ah-in-f14.1e100.net → 172.217.17.78 ✓
   🟢 Forward-confirmed: ams16s30-in-f14.1e100.net → 172.217.17.78 ✓

✅ 2a00:1450:400d:806::200e → bud02s21-in-x0e.1e100.net
   🟢 Forward-confirmed ✓
dns_propagation
Check if DNS has propagated by querying 8 public resolvers worldwide: Google (8.8.8.8, 8.8.4.4), Cloudflare (1.1.1.1, 1.0.0.1), OpenDNS, Quad9, Comodo, and Verisign. Shows whether all resolvers agree.

Parameters

domain string required — Domain to check (e.g. example.com)
record_type string optional — Record type to check (default: A)
Example output — google.com (A record) 
🌍 DNS Propagation Check for google.com (A)

Resolver                     │ Result                         │ Status
─────────────────────────────┼────────────────────────────────┼────────
Google (8.8.8.8)             │ 172.217.22.238                 │ ✅
Google Alt (8.8.4.4)         │ 172.217.22.238                 │ ✅
Cloudflare (1.1.1.1)         │ 172.217.20.206                 │ ✅
Cloudflare Alt (1.0.0.1)     │ 142.250.180.206                │ ✅
OpenDNS (208.67.222.222)     │ 142.250.74.206                 │ ✅
Quad9 (9.9.9.9)              │ 142.250.180.206                │ ✅
Comodo (8.26.56.26)          │ 142.250.180.206                │ ✅
Verisign (64.6.64.6)         │ 142.250.74.206                 │ ✅

✅ DNS is fully propagated (8/8 resolvers responding)
subdomain_finder
Discover common subdomains for a domain by checking ~80 common subdomain prefixes (www, mail, api, cdn, dev, staging, etc.). Groups results by category and shows resolved IP addresses.

Parameters

domain string required — Domain to scan for subdomains (e.g. example.com)
Example output — google.com (partial) 
🔍 Subdomain Discovery: google.com

Checking 80 common prefixes…

✅ Found 30+ subdomains:

🌐 Web:
   www.google.com                  → 142.250.180.196
   m.google.com                    → 142.250.180.206

📧 Mail:
   mail.google.com                 → 142.250.180.197
   smtp.google.com                 → 142.251.9.27

☁️ Services:
   api.google.com                  → 142.250.180.206
   cdn.google.com                  → 142.250.180.206
   docs.google.com                 → 142.250.180.206
   calendar.google.com             → 142.250.180.206
   chat.google.com                 → 142.250.180.206

📊 30/80 subdomains found
redirect_chain
Trace the full redirect chain for a URL. Shows every redirect hop with its HTTP status code and Location header, plus the final destination. Useful for debugging redirect loops or verifying HTTP→HTTPS upgrades.

Parameters

url string required — URL to trace (e.g. http://example.com)
max_redirects number optional — Maximum redirects to follow (default: 10)
Example output — http://google.com 
🔀 Redirect Chain: http://google.com

Hop 1: http://google.com
   → 301 Moved Permanently
   → Location: http://www.google.com/

Hop 2: http://www.google.com/
   → 200 OK ✅ (Final Destination)

══════════════════════════════════════════════
Total Hops: 2
ℹ️ www redirect detected
Final URL: http://www.google.com/
Total Time: 795ms
══════════════════════════════════════════════
tech_stack_detect
Detect the technology stack of a website by analyzing HTTP response headers and HTML content. Identifies web servers, CDNs, frameworks, CMS platforms, CSS frameworks, analytics tools, live chat widgets, and hosting providers.

Parameters

domain string required — Domain to analyze (e.g. example.com)
Example output — google.com 
🖥️ Tech Stack Detection: google.com

🖥️ Web Server: Google Web Server (GWS)

📋 Raw Headers:
   server: gws

══════════════════════════════════════════════
domain_age
Calculate the exact age of a domain and show its full registration timeline: creation date, last update, current date, and expiry. Includes a visual progress bar showing how much of the registration period has been used.

Parameters

domain string required — Domain to check age of (e.g. example.com)
Example output — google.com 
📅 Domain Age: google.com

📆 Registration Timeline:
├── 🟢 Created:  September 15, 1997
├── 🔄 Updated:  August 2, 2024
├── 📍 Current:  February 16, 2026
└── 🔴 Expires:  September 13, 2028

⏱️ Age: 28 years, 5 months, 1 days
👴 Internet veteran!

📊 Domain Longevity:
████████████████████████████░░ 92% of registration used
2 years, 7 months until expiry

══════════════════════════════════════════════
dns_compare
Compare DNS records of two domains side by side. Useful for comparing infrastructure setups, verifying DNS migration, or benchmarking against competitors. Shows A, AAAA, MX, NS, and TXT records in a table format.

Parameters

domain1 string required — First domain (e.g. google.com)
domain2 string required — Second domain (e.g. bing.com)
Example output — google.com vs bing.com 
🔄 DNS Comparison: google.com vs bing.com

Record Type  │ google.com                     │ bing.com
─────────────┼────────────────────────────────┼───────────────────────
A            │ 142.250.180.206                │ 150.171.28.10
             │                                │ 150.171.27.10
─────────────┼────────────────────────────────┼───────────────────────
AAAA         │ 2a00:1450:400d:80f::200e       │ 2620:1ec:33::10
             │                                │ 2620:1ec:33:1::10
─────────────┼────────────────────────────────┼───────────────────────
MX           │ smtp.google.com (pri 10)       │ bing-com.mail.protection
             │                                │   .outlook.com (pri 10)
─────────────┼────────────────────────────────┼───────────────────────
NS           │ ns1-4.google.com               │ ns1-4.msft.net
port_check
Check if network ports are open on a domain. By default scans 16 common ports (HTTP, HTTPS, SSH, FTP, SMTP, DNS, IMAP, POP3, MySQL, PostgreSQL, etc.). You can also specify a custom list of ports. Includes service identification and security insights.

Parameters

domain string required — Domain or IP to scan (e.g. example.com)
ports string optional — Comma-separated port numbers or "common" (default: common)
Example output — google.com (ports 80, 443) 
🔌 Port Check: google.com

Resolved to: 172.217.20.206

Port    │ Service       │ Status
────────┼───────────────┼───────────
80      │ HTTP          │ ✅ Open
443     │ HTTPS         │ ✅ Open

══════════════════════════════════════════════
📊 Results: 2 open, 0 closed out of 2 ports checked
⏱️ Scan completed in 0.0s

✅ Web services: HTTP and HTTPS are both open (good!)
══════════════════════════════════════════════

Prompt Templates

Domain Inspector includes 4 built-in prompt templates that orchestrate multiple tools for common workflows. Your AI assistant can use these directly.

domain-check
Run a full domain intelligence report with executive summary. Returns DNS, WHOIS, email security, SSL, HTTP headers, tech stack, and domain age — then provides an overall health assessment, urgent issues, and prioritized recommendations.

Parameters

domain string required — Domain to analyze
security-audit
Perform a security audit by running ssl_check, http_headers_check, email_config_check, and port_check in sequence. Summarizes findings with an overall security rating and recommendations.

Parameters

domain string required — Domain to audit
compare-domains
Compare two domains side by side using dns_compare, ssl_check, and http_headers_check. Highlights key differences in DNS configuration, SSL certificates, and security headers.

Parameters

domain1 string required — First domain
domain2 string required — Second domain
find-subdomains
Discover all subdomains using subdomain_finder and analyze what each one likely serves (mail, API, CDN, etc.) based on its name and IP. Summarizes the domain's infrastructure footprint.

Parameters

domain string required — Domain to scan

API Endpoints

Domain Inspector exposes the following HTTP endpoints:

POST /mcp
Main MCP JSON-RPC endpoint. Supports Streamable HTTP transport with session management. Send an initialize request to start a session, then use tools/call, prompts/list, resources/list, etc.
GET /health
Health check endpoint. Returns JSON with server status, tool count, and version. Use this for uptime monitoring.
Example response 
{ "status": "ok", "tools": 15, "version": "2.0.0" }
GET /.well-known/mcp/server-card.json
Server metadata card following the MCP specification. Contains server name, description, version, tool definitions, and configuration schema.
GET /icon.svg
Server icon in SVG format for use in MCP client UIs.

Frequently Asked Questions

What is Domain Inspector?
Domain Inspector is an MCP (Model Context Protocol) server that gives AI assistants the ability to perform domain intelligence lookups. It provides 15 tools covering DNS records, WHOIS registration data, SSL/TLS certificates, email security (SPF/DKIM/DMARC), HTTP security headers, technology stack detection, subdomain discovery, port scanning, and more.
What is MCP?
The Model Context Protocol (MCP) is an open standard by Anthropic that allows AI assistants to connect to external tools and data sources. It enables AI models to take actions and access real-time information through a standardized JSON-RPC interface over HTTP. Think of it as a universal plugin system for AI.
How do I connect?
Add the server URL (https://mcpdns.onrender.com/mcp) to your MCP client's configuration. Most clients (Claude Desktop, Cursor, Windsurf, VS Code) have a settings panel or JSON config file where you can add MCP servers. Once connected, your AI assistant automatically gains access to all 15 tools.
What data sources does it use?
All data comes from public sources and standard network protocols: DNS queries via the system resolver, public WHOIS registries, direct TLS connections for certificate inspection, HTTP response headers, and HTML content analysis. No private databases, third-party APIs, or paid services are used.
Is it safe to use?
Yes. All tools are read-only and only query publicly available data. DNS lookups, WHOIS queries, and SSL checks are standard operations that every web browser performs. Subdomain scanning checks only ~80 common prefixes, and port checking uses conservative timeouts with a limited set of well-known ports.
How fast are the responses?
Most individual tools respond in under 3 seconds. DNS lookups and SSL checks are typically under 1 second. The full domain_report tool, which runs 7 checks in parallel, usually completes in 3–8 seconds depending on the target domain. Subdomain scanning takes longer (10–20 seconds) as it checks ~80 prefixes.
What are the rate limits?
There are currently no artificial rate limits on the server. However, the underlying DNS and WHOIS protocols have their own natural rate limits. For responsible use, avoid running bulk scans of hundreds of domains in rapid succession.
Can I use it for commercial purposes?
Yes, you can use Domain Inspector for commercial purposes including client audits, security assessments, and competitive analysis. The data returned is from public sources and is not proprietary.