usememos/memos · warning

hostname resolved to no addresses

Error message

hostname resolved to no addresses

What it means

After DNS resolution succeeds but every returned entry either has a nil IP or was filtered out, the resolver path in internal/httpgetter returns this error. In practice it means the hostname exists in DNS but yielded no usable addresses, or all addresses were rejected as internal.

Source

Thrown at internal/httpgetter/html_meta.go:98

	addrs, err := lookupIPAddr(ctx, host)
	if err != nil {
		return nil, errors.Errorf("failed to resolve hostname: %v", err)
	}

	ips := make([]net.IP, 0, len(addrs))
	for _, addr := range addrs {
		ip := addr.IP
		if ip == nil {
			continue
		}
		if isInternalIP(ip) {
			return nil, errors.Wrapf(ErrInternalIP, "host=%s, ip=%s", host, ip.String())
		}
		ips = append(ips, ip)
	}
	if len(ips) == 0 {
		return nil, errors.New("hostname resolved to no addresses")
	}

	return ips, nil
}

func isInternalIP(ip net.IP) bool {
	return ip.IsLoopback() || ip.IsPrivate() || ip.IsLinkLocalUnicast() || ip.IsUnspecified()
}

func validateURL(urlStr string) error {
	u, err := url.Parse(urlStr)
	if err != nil {
		return errors.New("invalid URL format")
	}

	if u.Scheme != "http" && u.Scheme != "https" {
		return errors.New("only http/https protocols are allowed")
	}

View on GitHub (pinned to 14d757ce1f)

Solutions

1. Verify the host actually resolves publicly: `dig +short <hostname>` should return at least one non-private IP
2. If the service is internal-only, do not pass it to the metadata fetcher; the SSRF guard will never allow it
3. Fix the DNS zone if it returns empty answers for a supposed-to-be-public name

// Verify host resolves to at least one public IP before fetching
func resolvesPublicly(host string) (bool, error) {
  addrs, err := net.LookupIP(host)
  if err != nil { return false, err }
  n := 0
  for _, ip := range addrs {
    if !ip.IsLoopback() && !ip.IsPrivate() && !ip.IsLinkLocalUnicast() && !ip.IsUnspecified() { n++ }
  }
  return n > 0, nil
}

// Degrade to no-preview on resolution anomalies
if _, err := getter.GetHTMLMeta(u); err != nil {
  if strings.Contains(err.Error(), "no addresses") { return nil /* skip preview */ }
  return err
}

When it happens

Trigger: A DNS response containing only CNAME-less/nil-IP records, a hostname resolving exclusively to private IPs that get stripped after the internal-IP check path, or a transient DNS misconfiguration returning empty answers.

Common situations: Internal hostnames (only private A records) passed to the link preview fetcher; broken split-horizon DNS where the public zone returns no A records; records that exist (NXDOMAIN is not returned) but carry no address data.

Related errors

• internal IP addresses are not allowed
• only http/https protocols are allowed
• too many redirects
• invalid URL format
• empty hostname

AI-assisted analysis of usememos/memos@14d757ce1f (2026-08-15). Data as JSON: /api/errors/0d235722f1011ff4. Report an issue: GitHub.