mongodb/node-mongodb-native · error · MongoAPIError

Server record does not have at least one more domain level t

Error message

Server record does not have at least one more domain level than parent URI

What it means

Thrown by checkParentDomainMatch() during SRV/TXT-record validation when the srvHost has fewer than three dot-separated parts AND the resolved record's host has the same or fewer parts than the srvHost. The driver requires SRV-returned hosts to live at least one DNS level below the srvHost to prevent a compromised DNS server from redirecting the client to arbitrary hosts. It surfaces as a MongoAPIError and originates from srv_polling.ts and connection_string.ts.

Source

Thrown at src/utils.ts:1181

  const allCharacterBeforeFirstDot = /^.*?\./;
  const srvIsLessThanThreeParts = normalizedSrvHost.split('.').length < 3;
  // Remove all characters before first dot
  // Add leading dot back to string so
  //   an srvHostDomain = '.trusted.site'
  //   will not satisfy an addressDomain that endsWith '.fake-trusted.site'
  const addressDomain = `.${normalizedAddress.replace(allCharacterBeforeFirstDot, '')}`;
  let srvHostDomain = srvIsLessThanThreeParts
    ? normalizedSrvHost
    : `.${normalizedSrvHost.replace(allCharacterBeforeFirstDot, '')}`;

  if (!srvHostDomain.startsWith('.')) {
    srvHostDomain = '.' + srvHostDomain;
  }
  if (
    srvIsLessThanThreeParts &&
    normalizedAddress.split('.').length <= normalizedSrvHost.split('.').length
  ) {
    throw new MongoAPIError(
      'Server record does not have at least one more domain level than parent URI'
    );
  }
  if (!addressDomain.endsWith(srvHostDomain)) {
    throw new MongoAPIError('Server record does not share hostname with parent URI');
  }
}

/**
 * Perform a get request that returns status and body.
 * @internal
 */
export function get(
  url: URL | string,
  options: http.RequestOptions = {}
): Promise<{ body: string; status: number | undefined }> {
  return new Promise((resolve, reject) => {
    /* eslint-disable prefer-const */

View on GitHub (pinned to 3366c21a63)

Solutions

Use a srvHost with at least three labels (e.g. _mongodb._tcp.cluster.example.com) so children can be one level deeper.
Ensure every SRV target hostname is a proper subdomain of the srvHost.
If SRV is not required, switch to a standard mongodb:// seedlist connection string, which bypasses SRV hostname validation.
Work with your DNS/Atlas administrator to correct the published SRV records.

Example fix

// before
const uri = 'mongodb+srv://db.srv/'; // two-label srvHost; SRV child not deeper => MongoAPIError

// after
const uri = 'mongodb+srv://cluster0.example.com/'; // three-label srvHost with valid child targets

Defensive patterns

Strategy: try-catch

Try / catch

try {
  await client.connect();
} catch (err) {
  if (err instanceof MongoAPIError && /does not have at least one more domain level/.test(err.message)) {
    throw new Error('srvHost must have >=3 labels and SRV targets must be deeper subdomains', { cause: err });
  }
  throw err;
}

Prevention

Use a three-or-more-label srvHost for mongodb+srv:// connections.
Verify SRV targets with `dig SRV _mongodb._tcp.<srvHost>` before deploying.
Prefer the Atlas-generated connection string, which satisfies the rules by construction.

When it happens

Trigger: Using `mongodb+srv://short.srv/` where short.srv has < 3 labels (e.g. a two-label host) and the SRV record returns a host that does not add a subdomain level. Also from TXT record hostname checks during initial connection-string resolution.

Common situations: Misconfigured Atlas/seedlist SRV records; using mongodb+srv:// with a custom short hostname that violates the cross-driver SRV rules; a private DNS setup where SRV target hostnames are siblings of (rather than children of) the srvHost.

Related errors

AI-assisted analysis of mongodb/node-mongodb-native@3366c21a63 (2026-08-04). Data as JSON: /data/errors/c32caa5592db0cad.json. Report an issue: GitHub.