# AgentsToolsHub DNSBL Check

> AgentsToolsHub DNSBL Check is a paid API for AI agents from agentstoolshub.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Checks a single IPv4 address against four major DNS-based email blocklists (Barracuda, SpamCop, SORBS, DroneBL) to determine if it is listed for spam or abuse.

## Facts

- Endpoint: GET https://agentstoolshub.com/api/v1/security/dnsbl-check?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentstoolshub-dnsbl-check-5277a62d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ToWBAUJAPV33AY87nHJS4

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 agentstoolshub-dnsbl-check-5277a62d
```

Example prompt: Can you check if the IP 198.51.100.42 is listed on any of the major email blocklists like Barracuda, SpamCop, SORBS, or DroneBL before I try sending mail from that server?

## When to prefer this

Choose this endpoint when you need a quick, multi-blocklist reputation check for a single IPv4 address prior to sending email, diagnosing mail delivery failures, or vetting a new outbound mail server. It is ideal for pre-flight email deliverability checks covering the four most widely used blocklists in one call, saving the overhead of querying each DNSBL manually.

## Known failure modes

- Invalid or malformed IPv4 address returns an error response
- Private or reserved IP ranges may not be meaningful to check
- Network timeouts querying one or more DNSBL providers could yield partial results
- Rate limiting may occur if the endpoint is called too frequently
- IPv6 addresses are not supported

## How this service works

Check an IPv4 address against four major public DNS blocklists (Barracuda, SpamCop, SORBS, DroneBL). A listing means the IP sent spam or abuse — mail sent from it will bounce or junk across the internet. The pre-flight check before sending email from any server or relay. Use this when an agent needs to is this IP on the major email blocklists?.

## Output

Returns the blocklist status of the queried IPv4 address across four major DNSBL providers (Barracuda, SpamCop, SORBS, DroneBL), indicating whether the IP is listed on each and what that listing implies about its reputation for spam or abuse.

## 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",
     "required": [
      "ip"
     ],
     "properties": {
      "ip": {
       "type": "string",
       "description": "IPv4 address"
      }
     }
    }
   },
   "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/agentstoolshub-dnsbl-check-5277a62d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentstoolshub.com](https://www.zero.xyz/host/agentstoolshub.com/llms.txt)