# DNS SRV Record Lookup for STUN over UDP

> DNS SRV Record Lookup for STUN over UDP is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.006/call, status unknown (last checked 2026-10-14).

Looks up SRV records at _stun._udp.{hostname} to return STUN service discovery information for a given registrable domain.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-srv-stun?utm_source=zero.xyz
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-srv-record-lookup-for-stun-over-udp-6c4721fa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3QTxP3xEB3tzRxYcwTG8S

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-srv-record-lookup-for-stun-over-udp-6c4721fa -d '<json body>'
```

Example prompt: Look up the STUN SRV record over UDP for the domain example.com so I can find out which STUN server it advertises.

## When to prefer this

Use this endpoint when an agent needs to discover a STUN server for a given domain via DNS SRV record lookup (specifically at _stun._udp.{hostname}), typically for WebRTC, VoIP, or NAT traversal configuration. Prefer the unpaid sandbox endpoint (POST /v1/sandbox/dns-srv-stun) for testing before using this paid endpoint at $0.006 USDC per call.

## Known failure modes

- Domain has no _stun._udp SRV record — returns empty or not-found response
- Invalid or malformed hostname input — validation error
- DNS resolution timeout or upstream DNS failure
- Non-registrable or non-existent domain returns no records

## How this service works

Call when an agent needs SRV records at _stun._udp.{hostname} for STUN over UDP. The caller sends the registrable domain, not the underscored name. Send JSON {"hostname":"example.com"}. Exact $0.006 USDC on Base. Try unpaid POST /v1/sandbox/dns-srv-stun first.

## Output

Returns the SRV record data found at _stun._udp.{hostname}, typically including the target STUN server hostname, port, priority, and weight as defined in the DNS SRV record.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "hostname": {
   "type": "string",
   "examples": [
    "example.com"
   ],
   "maxLength": 253,
   "minLength": 1,
   "description": "Public DNS hostname such as example.com. Not a URL, not an IP literal, and not a private name."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dns-srv-record-lookup-for-stun-over-udp-6c4721fa/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)