DNS Gurus
Cached · just now
77/100 SECURITY SCORE

Certificate Information

Subject
CN=groupon.com
Issuer
C=US, O=Let's Encrypt, CN=R12
Valid From
November 19, 2025
Valid Until
February 17, 2026 22 days
Public Key
RSA 2048 bit Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
A3:90:5D:2C:09:5E:E3:80:7A:1A:D8:A8:DF:CF:AF:49:3D:1B:84:5D:FE:88:57:FE:6D:E8:A3:8A:8E:40:A2:58
Alternative Names
43 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
Present
max-age=15768000
Content-Security-Policy
Missing
Not configured
X-Frame-Options
Excellent
DENY
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
  • • Add Content-Security-Policy header to prevent XSS attacks
  • • 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