# AdminKit

> Machine Protocol Edge: free tools to check your IP, DNS and mail setup today, and
> a protective layer rolling out for the connections devices and AI agents make that
> are not plain web traffic — device DNS, MQTT, Modbus and MCP/A2A.
> A brand of Netbase Enterprise Solutions and Applications Joint Stock Company (Netbase JSC), Hanoi, Vietnam. No account needed for the core tools.

## Key pages

- [Home](https://adminkit.net/): what is my IP, and is my connection safe — free, no account.
- [All tools](https://adminkit.net/tools/): every free AdminKit check in one place.
- [Products](https://adminkit.net/products/protective-dns/): Protective DNS, MCP/Agent Gateway, Agent Trust API, Secure Broker, OT Remote Access, Check API.
- [Guides](https://adminkit.net/guides/): answer-first how-tos with sources.
- [Developers](https://adminkit.net/developers/): API and MCP server overview.
- [About](https://adminkit.net/about/) · [Contact](https://adminkit.net/contact/) · [Security](https://adminkit.net/security/)

## Tools

- [What is my IP](https://adminkit.net/tools/my-ip/) — See your public IPv4/IPv6, ISP, ASN and approximate location. (live)
- [DNS lookup](https://adminkit.net/tools/dns-lookup/) — A, AAAA, MX, TXT, NS, CAA and more for any domain. (live)
- [MX lookup](https://adminkit.net/tools/mx-lookup/) — Mail exchanger records and their priorities for a domain. (live)
- [Reverse DNS (PTR)](https://adminkit.net/tools/reverse-dns/) — Resolve an IP address back to its hostname. (live)
- [Whois / RDAP](https://adminkit.net/tools/whois/) — Registrar, registration dates, status and nameservers for a domain or IP. (live)
- [Subnet calculator](https://adminkit.net/tools/subnet-calculator/) — IPv4 and IPv6 subnet, mask, range and host count math. (live)
- [DNS resolver / leak test](https://adminkit.net/tools/dns-resolver-test/) — See which DNS resolver your connection is actually using. Coming with the API. (coming with the API)
- [SPF check](https://adminkit.net/tools/spf-check/) — Validate your domain's SPF record and lookup count. (live)
- [DMARC check](https://adminkit.net/tools/dmarc-check/) — Validate your domain's DMARC policy and reporting tags. (live)
- [DKIM check](https://adminkit.net/tools/dkim-check/) — Validate a DKIM selector's public key record. (live)
- [Blacklist (DNSBL) check](https://adminkit.net/tools/blacklist-check/) — Check an IP or domain against DNS-based blocklists. (coming with the API)
- [Open ports on my IP](https://adminkit.net/tools/port-check/) — Scan your own public IP for commonly exposed device ports. (coming with the API)
- [SSL/TLS check](https://adminkit.net/tools/ssl-check/) — Certificate chain, expiry and protocol strength for a host. (coming with the API)
- [HTTP security headers](https://adminkit.net/tools/http-headers/) — Check Content-Security-Policy, HSTS and other response headers. (coming with the API)
- [MQTT exposure](https://adminkit.net/tools/mqtt-check/) — Check whether an MQTT broker accepts unauthenticated connections. (coming with the API)
- [Modbus exposure](https://adminkit.net/tools/modbus-check/) — Check whether a Modbus/TCP device is reachable from the internet. (coming with the API)
- [MCP endpoint check](https://adminkit.net/tools/mcp-check/) — Check whether an MCP server requires authentication. (coming with the API)
- [MAC vendor lookup](https://adminkit.net/tools/mac-lookup/) — Look up the manufacturer that registered a MAC address prefix. Coming soon. (coming with the API)
- [User agent](https://adminkit.net/tools/user-agent/) — Parse and explain your browser's User-Agent string. (live)

## Guides

- [How to Secure an MCP Server | AdminKit Guide](https://adminkit.net/guides/how-to-secure-an-mcp-server/) — Secure an MCP server with OAuth per spec, a tool allowlist, and filtering for prompt injection in tool responses. A practical checklist with sources. (live)
- [IPv6 at Home: Why No NAT Means a Firewall | AdminKit](https://adminkit.net/guides/ipv6-home-devices-need-a-firewall/) — IPv6 gives each home device its own public address, with no NAT in the way. Without a proper firewall, devices can be reachable directly from the internet. (live)
- [Is Modbus TCP (Port 502) Exposed? | AdminKit](https://adminkit.net/guides/is-modbus-tcp-502-exposed/) — Modbus TCP has no built-in authentication, so anything reachable on port 502 can usually be read or written by anyone. Check your exposure and fix it. (live)
- [Is My Router's DNS Hijacked? | AdminKit Guide](https://adminkit.net/guides/is-my-router-dns-hijacked/) — DNS hijacking silently redirects your traffic by changing which resolver you use. Check the signs, confirm your actual resolver, and fix a hijacked router. (live)
- [Is Port 1883 (MQTT) Open on My Router? | AdminKit](https://adminkit.net/guides/is-port-1883-mqtt-open/) — Port 1883 is the default MQTT port, and MQTT allows anonymous connections by default. Check if yours is exposed to the internet, and how to close it. (live)
- [SPF, DKIM and DMARC Explained | AdminKit Guide](https://adminkit.net/guides/spf-dkim-dmarc-explained/) — SPF lists who can send your mail, DKIM signs it, DMARC says what to do if both fail. See real record examples and how to check your own domain. (live)
- [What Is CGNAT and Why It Confuses Sites | AdminKit](https://adminkit.net/guides/what-is-cgnat/) — CGNAT means your ISP shares one public IP among many customers. Learn why that causes blacklists, CAPTCHAs and shared blame, and how to check if you have it. (live)
- [Why Is My IP Address Blacklisted? | AdminKit Guide](https://adminkit.net/guides/why-is-my-ip-blacklisted/) — An IP lands on a blacklist when spam, malware or abuse traps trace back to it. Check which list flagged you, find the cause, then request delisting. (live)

## Contact

- General: hello@adminkit.net
- Security disclosure: security@adminkit.net
- Privacy: privacy@adminkit.net
- Phone / WhatsApp: +84 937 869 689 (https://wa.me/84937869689)
- Full text version: https://adminkit.net/llms-full.txt