# DNS SRV Record Lookup for Email Submission (Implicit TLS)

> DNS SRV Record Lookup for Email Submission (Implicit TLS) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-23).

Looks up SRV records at _submissions._tcp.{hostname} for locating implicit TLS email submission servers for a given registrable domain.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-srv-submissions?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-srv-record-lookup-for-email-submission-implicit-tls-02030d33
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_V3S4fJl77cC95N360rTlM

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-email-submission-implicit-tls-02030d33 -d '<json body>'
```

Example prompt: Can you look up the SRV records for implicit TLS email submission for the domain example.com? I want to find out what host and port handle SMTP submission there.

## When to prefer this

Use this endpoint when an agent needs to discover the implicit TLS (port 465-style) email submission server for a domain via DNS SRV service records, specifically querying _submissions._tcp. Prefer the free sandbox alternative (POST /v1/sandbox/dns-srv-submissions) for testing. Choose this over generic DNS lookup tools when the target record type is specifically the email submission SRV record.

## Known failure modes

- Domain not found or no SRV record exists at _submissions._tcp.{hostname} — returns empty or NXDOMAIN result
- Invalid hostname format — returns validation error
- DNS resolution timeout — service may return an error or timeout response
- Hostname exceeds 253 characters — rejected by input validation

## How this service works

Call when an agent needs SRV records at _submissions._tcp.{hostname} for implicit TLS submission. The caller sends the registrable domain, not the underscored name. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/dns-srv-submissions first.

## Output

Returns SRV record data for _submissions._tcp.{hostname}, including the target host, port, priority, and weight for the implicit TLS email submission server associated with the given domain.

## 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-email-submission-implicit-tls-02030d33/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)