DNS Gurus
Cached · just now
93/100 SECURITY SCORE

Detected Technologies

See all in URL Inspect 3
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Certificate Information

Subject
CN=*.fastmail.com
Issuer
C=US, O=Let's Encrypt, CN=R12
Valid From
April 02, 2026
Valid Until
July 01, 2026 88 days
Public Key
RSA 2048 bit Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
F5:F9:CF:A1:72:B3:33:BB:10:A5:D1:C9:C5:1B:3F:87:0D:B1:F1:FC:58:C5:4B:90:2C:6B:5A:16:1B:0F:BF:4D
Alternative Names
4 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
Gravatar logo
Basic
default-src; script-src; style-src; +5 more Analyze
Content-Security-Policy-Report-Only
Missing
Not configured Analyze
X-Frame-Options
Excellent
DENY
X-Content-Type-Options
Good
nosniff
Referrer-Policy
Good
strict-origin-when-cross-origin
Permissions-Policy
Present
accelerometer=(), ambient-light-sensor=(), battery=(); +17 more
Recommendations
  • • Improve CSP by adding more specific directives and removing 'unsafe-inline'

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