DNS Rebinding Check

What It Does

DNS rebinding is the rotation of a domain's answer between public and private addresses across queries — that's how attackers escape the same-origin policy. This endpoint runs the actual rotation test: 3 queries spaced 2 seconds apart, with `cd=1` to bypass resolver-side filtering, looking for round-to-round changes in the IP set's public/private mix. In parallel it queries multiple public resolvers (Cloudflare, Google, Quad9) and reports which ones drop RFC 1918 results per RFC 6303 — telling you which of your actual users (depending on which resolver they use) are exposed. Static checks still run: detection of RFC 1918, loopback (127/8), link-local (169.254/16), cloud metadata (169.254.169.254), CGNAT (RFC 6598), TEST-NET ranges (RFC 5737), and the IPv6 equivalents (fc00::/7, fe80::/10, NAT64, Teredo, 6to4).

Why It's Useful

Most "DNS rebinding checkers" only test for static private IPs and call that "rebinding" — but real rebinding is *rotation*, not static misconfiguration. The multi-query rotation test makes the endpoint live up to its name. The multi-resolver filter visibility answers the question users actually have: "are my users exposed?" — public resolvers (1.1.1.1, 8.8.8.8) drop RFC 1918 per RFC 6303, but internal corporate resolvers often don't, and the response shows you which.

Use Cases

Parameters

Response Fields

Code Examples

curl "https://api.edgedns.dev/v1/dns/rebinding" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d "domain=example.com"

const response = await fetch(
  'https://api.edgedns.dev/v1/dns/rebinding?domain=example.com',
  {
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY'
    }
  }
);

const data = await response.json();
console.log(data);

import requests

response = requests.get(
    'https://api.edgedns.dev/v1/dns/rebinding',
    headers={'Authorization': 'Bearer YOUR_API_KEY'},
    params={
    'domain': 'example.com'
    }
)

data = response.json()
print(data)

Related Endpoints

External References

Learn more about the standards and protocols behind this endpoint.