DNS Gurus

SSL Verification Bypassed

The server's SSL certificate could not be verified. The analysis was completed using insecure mode. Data may be less reliable.

Reason:

Hostname Mismatch - certificate is issued for www.gbv.de, not for gbv.de

Cached · just now
84/100 SECURITY SCORE

Certificate Information

Subject
C=DE, ST=Niedersachsen, O=Verbundzentrale des Gemeinsamen Bibliotheksverbundes (VZG), CN=www.gbv.de
Issuer
C=GR, O=Hellenic Academic and Research Institutions CA, CN=GEANT TLS RSA 1
Valid From
December 03, 2025
Valid Until
December 03, 2026 212 days
Public Key
RSA 4096 bit Strong
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
46:99:97:48:1E:CF:75:1F:7F:A0:84:B6:45:64:90:44:FC:06:CD:07:AD:DA:D7:B6:0C:E4:86:C6:62:DC:74:90
Alternative Names
1 domains

Security Configuration

TLS Protocols
TLS 1.2
Forward Secrecy
Limited (Check cipher configuration)
Warnings
  • • TLS 1.3 is not supported (recommended)

HTTP Security Headers

Status
Strict-Transport-Security
Present
max-age=15768000; includeSubDomains
Content-Security-Policy
Basic
default-src; img-src; style-src; +2 more Analyze
Content-Security-Policy-Report-Only
Missing
Not configured Analyze
X-Frame-Options
Good
SAMEORIGIN
X-Content-Type-Options
Good
nosniff
Referrer-Policy
Missing
Not configured
Permissions-Policy
Missing
Not configured
Recommendations
  • • Increase HSTS max-age to at least 1 year and add includeSubDomains
  • • Improve CSP by adding more specific directives and removing 'unsafe-inline'
  • • 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
Configured (Restricts certificate issuance)
Current Issuer
Not Authorized (Potential misconfiguration)
Authorized CAs
sectigo.com harica.gr letsencrypt.org
CAA Issues
  • • CRITICAL: Current certificate issuer 'C=GR, O=Hellenic Academic and Research Institutions CA, CN=GEANT TLS RSA 1' is NOT authorized by CAA records. Authorized CAs: sectigo.com, harica.gr, letsencrypt.org
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

Subject Alternative Names

1 domain
www.gbv.de