# H323CS TCP SRV Record Lookup via Cloudflare DoH

> H323CS TCP SRV Record Lookup via Cloudflare DoH is a paid API for AI agents from dns.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-18).

Returns SRV records for the H.323 Call Signaling (_h323cs._tcp) service of a given domain via Cloudflare DNS over HTTPS.

## Facts

- Endpoint: GET https://dns.intel.rallylive.ca/dns/srv/h323cs-tcp?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/h323cs-tcp-srv-record-lookup-via-cloudflare-doh-dc1d4fbb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XBsoufy5Rj8Y-i7TIvzRi

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 h323cs-tcp-srv-record-lookup-via-cloudflare-doh-dc1d4fbb
```

Example prompt: Can you look up the H.323 call signaling SRV record for example.com so I can find out what host and port its h323cs TCP service is running on?

## When to prefer this

Use this endpoint when you need to discover an H.323 Call Signaling service endpoint for a specific domain via DNS SRV lookup, particularly when you want results from Cloudflare's 1.1.1.1 resolver with privacy-preserving DNS over HTTPS. Prefer this over manual DNS tools when automating VoIP infrastructure discovery or verifying H.323 configuration in an agent workflow.

## Known failure modes

- Domain has no _h323cs._tcp SRV record configured (NXDOMAIN or empty answer)
- Domain does not exist (NXDOMAIN)
- Cloudflare DoH upstream timeout or unavailability
- Malformed or missing domain input parameter
- DNS SERVFAIL due to broken zone configuration

## How this service works

H323CS service discovery (_h323cs._tcp.<domain>): SRV records with priority, weight, port and target host, from Cloudflare DoH. Tells a client where the domain's h323cs service lives without guessing hosts. $0.01 per lookup.

## Output

Returns DNS SRV record data for _h323cs._tcp.<domain> including one or more records each with priority, weight, port number, and target hostname, along with the TTL and DNS response code, as resolved by Cloudflare's DNS over HTTPS service.

## 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/h323cs-tcp-srv-record-lookup-via-cloudflare-doh-dc1d4fbb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dns.intel.rallylive.ca](https://www.zero.xyz/host/dns.intel.rallylive.ca/llms.txt)