SSL Certificate Analysis for mx.katayanagi.com - Security Grade & TLS Configuration

Open Cached · just now

76/100 SECURITY SCORE

Detected Technologies

See all in URL Inspect 1

Let's Encrypt

Certificate Information

Subject

CN=nextclass.it

Issuer

C=US, O=Let's Encrypt, CN=R13

Valid From

May 18, 2026

Valid Until

August 16, 2026 77 days

Public Key

RSA 4096 bit Strong

Signature Algorithm

SHA256-RSA

SHA-256 Fingerprint

03:91:59:04:5C:6C:53:AE:F6:26:ED:52:2F:AD:B5:F5:73:EE:26:A2:EF:4B:9E:27:FF:3F:76:20:81:2D:09:EE

Alternative Names

90 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

Missing

Not configured

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

Missing

Not configured

Referrer-Policy

Missing

Not configured

Permissions-Policy

Missing

Not configured

Recommendations

• Add Strict-Transport-Security header with max-age of at least 1 year
• Add Content-Security-Policy header to prevent XSS attacks
• Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking
• 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