DNS Gurus
Cached · just now
86/100 SECURITY SCORE

Certificate Information

Subject
CN=atlas-alerts.mit.edu
Issuer
C=US, O=Let's Encrypt, CN=R13
Valid From
January 04, 2026
Valid Until
April 04, 2026 60 days
Public Key
RSA 2048 bit Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
7F:B8:99:00:D8:2E:5D:1C:23:B8:10:C7:28:E2:56:60:54:98:4F:E9:0D:3A:49:B7:EF:2F:6B:8E:41:29:5D:75
Alternative Names
35 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=259200
Content-Security-Policy
Missing
Not configured
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
  • • Increase HSTS max-age to at least 1 year and add includeSubDomains
  • • 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
Configured (Restricts certificate issuance)
Current Issuer
Authorized (Matches CAA policy)
Authorized CAs
letsencrypt.org globalsign.com
Recommendations
  • • Consider using critical flag (flags=128) for stricter CAA enforcement
  • • Consider adding 'iodef' records to receive notifications about unauthorized certificate issuance attempts
  • • Consider adding 'issuewild' records to control wildcard certificate issuance