# HostKarma Black DNSBL Lookup

> HostKarma Black DNSBL Lookup is a paid API for AI agents from ip.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).

Checks whether a given IPv4 address is listed on the HostKarma Black DNSBL (hostkarma.junkemailfilter.com) and returns listed status, return codes, and reason text.

## Facts

- Endpoint: GET https://ip.intel.rallylive.ca/ip/blacklist/hostkarma-black?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hostkarma-black-dnsbl-lookup-98e21e42
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rN21Y4AxxGmSUP6uTHpr8

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 hostkarma-black-dnsbl-lookup-98e21e42
```

Example prompt: Can you check if the IP address 203.0.113.47 is listed on the HostKarma Black spam blacklist and tell me whether it's flagged and why?

## When to prefer this

Choose this endpoint when you need a precise, single-list check against the HostKarma Black DNSBL specifically — ideal when you want authoritative HostKarma listing status with reason codes rather than a multi-list aggregated score. Prefer this over generic multi-DNSBL tools when HostKarma is a required check for your email filtering or IP reputation pipeline.

## Known failure modes

- Invalid IPv4 address format returns an error
- DNS resolution failure via Cloudflare DoH returns a lookup error
- IP not listed returns a negative result with no reason text
- Network timeout from Cloudflare DoH results in an error response

## How this service works

Is this IPv4 address listed on hostkarma black (hostkarma.junkemailfilter.com)? Performs the DNSBL query (reversed octets under hostkarma.junkemailfilter.com, via Cloudflare DoH) and returns listed yes/no with the return codes and, where the list publishes one, the reason text. One list, one precise answer. $0.01 per lookup.

## Output

Returns whether the IPv4 address is listed on the HostKarma Black DNSBL, the DNS return codes from the query, and, where available, the human-readable reason text explaining why the address is listed.

## 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/hostkarma-black-dnsbl-lookup-98e21e42/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ip.intel.rallylive.ca](https://www.zero.xyz/host/ip.intel.rallylive.ca/llms.txt)