# DNS A Record Lookup for MX Subdomain

> DNS A Record Lookup for MX Subdomain is a paid API for AI agents from dns.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).

Looks up the A record for the mx.<domain> host via Cloudflare DoH and reports whether it exists, its IP records, and TTL

## Facts

- Endpoint: GET https://dns.intel.rallylive.ca/dns/host/mx/a?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-a-record-lookup-for-mx-subdomain-a4795cf1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6G7wKnIn9JN-RC1deSENu

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability dns-a-record-lookup-for-mx-subdomain-a4795cf1
```

Example prompt: Check if mx.acmecorp.com exists as a DNS A record — I want to know its IP addresses and TTL.

## When to prefer this

Use this endpoint when you need a fast, cheap ($0.01) existence and IP check specifically for the mx.<domain> host without enumerating all subdomains. Prefer it over generic DNS APIs when you want Cloudflare DoH-backed resolution with a simple REST interface and per-call micropayment pricing for lightweight spot-checks.

## Known failure modes

- Domain does not exist — NXDOMAIN returned, existence flag is false
- MX subdomain has no A record — host exists but no address record
- Malformed domain input — query fails with validation error
- Cloudflare DoH upstream timeout — transient failure
- Rate limiting or payment failure — 402 response if payment not attached

## How this service works

A record of mx.<domain>: looks up the mx host under the domain you give (A via Cloudflare DoH) and reports whether it exists, its records and TTL. Quick existence check for common hosts like mx without enumerating subdomains. $0.01 per lookup.

## Output

Returns whether the mx.<domain> A record exists, the resolved IP address(es), and the TTL of the record. If the host does not exist, indicates non-existence.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dns-a-record-lookup-for-mx-subdomain-a4795cf1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dns.intel.rallylive.ca](https://www.zero.xyz/host/dns.intel.rallylive.ca/llms.txt)