DNS Gurus
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89/100 SECURITY SCORE

Certificate Information

Subject
CN=synyx.de
Issuer
C=US, O=Let's Encrypt, CN=R12
Valid From
October 23, 2025
Valid Until
January 21, 2026 78 days
Public Key
RSA 2048 bit Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
17:9E:CD:3E:AC:2C:6F:F2:77:CF:06:17:6A:3B:9A:8F:39:D8:2A:88:46:47:C7:7D:ED:2D:F9:32:18:23:C2:75
Alternative Names
14 domains

Security Configuration

TLS Protocols
TLS 1.2 TLS 1.3
Forward Secrecy
Supported (Modern clients use PFS)

HTTP Security Headers

Status
Strict-Transport-Security
Good
max-age=31536000; includeSubDomains
Content-Security-Policy
Missing
Not configured
X-Frame-Options
Good
SAMEORIGIN
X-Content-Type-Options
Good
nosniff
Referrer-Policy
Good
strict-origin-when-cross-origin
Permissions-Policy
Present
geolocation=(), microphone=()
Recommendations
  • • Consider adding 'preload' to HSTS for maximum security
  • • Add Content-Security-Policy header to prevent XSS attacks

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