DNS Gurus
Cached · just now
87/100 SECURITY SCORE

Detected Technologies

See all in URL Inspect 1
Let's Encrypt logo Let's Encrypt

Certificate Information

Subject
CN=protonmail.com
Issuer
C=US, O=Let's Encrypt, CN=R13
Valid From
March 22, 2026
Valid Until
June 20, 2026 75 days
Public Key
RSA 4096 bit Strong
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
F7:D2:93:55:E2:B5:99:E0:3B:70:19:2F:4D:93:9E:F0:9D:2D:65:43:BC:04:71:13:2F:16:0D:E1:13:26:76:23
Alternative Names
6 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
Excellent
max-age=31536000; includeSubDomains; preload
Content-Security-Policy
Missing
Not configured Analyze
Content-Security-Policy-Report-Only
Missing
Not configured Analyze
X-Frame-Options
Missing
Not configured
X-Content-Type-Options
Good
nosniff
Referrer-Policy
Good
strict-origin-when-cross-origin
Permissions-Policy
Missing
Not configured
Recommendations
  • • Add Content-Security-Policy header to prevent XSS attacks
  • • Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking
  • • 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