DNS Gurus
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81/100 SECURITY SCORE

Certificate Information

Subject
CN=mail.kodai.com.tw
Issuer
C=US, O=Let's Encrypt, CN=R12
Valid From
October 07, 2025
Valid Until
January 05, 2026 34 days
Public Key
RSA 4096 bit Strong
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
D8:A4:04:21:F5:6C:1A:74:F4:48:30:12:B6:12:4F:FE:E3:27:A7:C5:65:3D:02:C7:32:2F:3B:67:24:20:F0:19
Alternative Names
1 domains

Security Configuration

TLS Protocols
TLS 1.0 TLS 1.1 TLS 1.2 TLS 1.3
Forward Secrecy
Supported (Modern clients use PFS)
Warnings
  • • TLS 1.1 is deprecated and should be disabled
  • • TLS 1.0 is deprecated and should be disabled

HTTP Security Headers

Status
Strict-Transport-Security
Present
max-age=31536000; includeSubdomains; preload
Content-Security-Policy
Basic
default-src; script-src; style-src; +2 more
X-Frame-Options
Missing
Not configured
X-Content-Type-Options
Missing
Not configured
Referrer-Policy
Missing
Not configured
Permissions-Policy
Missing
Not configured
Recommendations
  • • Increase HSTS max-age to at least 1 year and add includeSubDomains
  • • Improve CSP by adding more specific directives and removing 'unsafe-inline'
  • • Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking
  • • Add X-Content-Type-Options: nosniff
  • • Add Referrer-Policy header (recommended: strict-origin-when-cross-origin)
  • • Consider adding Permissions-Policy to control browser features

CAA Records (Certificate Authority Authorization)

CAA Records
Not Configured (Any CA can issue certificates)
CAA Issues
  • • No CAA records configured - any CA can issue certificates
Recommendations
  • • Implement CAA records to restrict which CAs can issue certificates for your domain
  • • This adds an extra layer of security against unauthorized certificate issuance
  • • Example: Add CAA record 'example.com. CAA 0 issue "letsencrypt.org"'
  • • Consider adding 'iodef' record to receive security incident reports

Subject Alternative Names

1 domain
mail.kodai.com.tw