# Syntexa AgentShelf Reverse DNS Lookup

> Syntexa AgentShelf Reverse DNS Lookup is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-01).

Performs reverse DNS lookup to retrieve PTR hostnames for a given public IPv4 or IPv6 address

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/reverse-dns?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/syntexa-agentshelf-reverse-dns-lookup-deaae674
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jb_YcKjvHrH67E3OfrzC7

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 syntexa-agentshelf-reverse-dns-lookup-deaae674 -d '<json body>'
```

Example prompt: What is the PTR hostname for the public IP address 8.8.8.8? Do a reverse DNS lookup and tell me what it resolves to.

## When to prefer this

Use this endpoint when an agent needs to resolve a public IP address back to its associated PTR/hostname records without any LLM involvement. It is priced per-call at $0.003 USDC and suits agentic workflows doing network analysis, log enrichment, or server identification. Prefer the free sandbox endpoint POST /v1/sandbox/reverse-dns for testing before paying. Do not use for private IP ranges.

## Known failure modes

- Private or reserved IP address submitted — endpoint explicitly rejects RFC1918 and loopback addresses
- Invalid IP format — non-parseable string returns a validation error
- No PTR record exists for the IP — empty or null hostname list returned
- Network/DNS timeout — upstream resolver fails to respond in time
- Payment failure — x402 USDC payment of $0.003 not processed correctly

## How this service works

Call when an agent needs PTR hostnames for a public IPv4 or IPv6 address (private addresses rejected). Exact $0.003 USDC. Prefer unpaid POST /v1/sandbox/reverse-dns first.

## Output

Returns one or more PTR hostnames associated with the provided public IP address, as resolved via reverse DNS. Private/reserved IP addresses are rejected and will return an error.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "ip": {
   "type": "string",
   "examples": [
    "8.8.8.8"
   ],
   "maxLength": 64,
   "minLength": 2,
   "description": "Public IPv4 or IPv6 address such as 8.8.8.8. Private, loopback, link-local, and metadata addresses are rejected."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/syntexa-agentshelf-reverse-dns-lookup-deaae674/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)