Aktivieren OCSP stapling für faster TLS handshakes
OCSP stapling lets der Server provide ein fresh revocation prüfen in der Client während der TLS handshake, avoiding ein separate round-trip in der CA.
- 1
Without OCSP stapling, the client must contact the CA's OCSP responder to check if the certificate is revoked — an extra round-trip that adds latency and leaks browsing history to the CA. With stapling, the server fetches the OCSP response and "staples" it to the TLS handshake.
- 2 RSA-Tool →
Verify the certificate supports OCSP by checking the Authority Information Access (AIA) extension, which contains the OCSP responder URL. Without this, stapling cannot work.
- 3 Hash-Rechner →
Hash the OCSP response to verify it has been updated recently. OCSP responses have a validity period (typically a few hours); the server must refresh them before expiry.
- 4
Configure your web server (nginx: ssl_stapling on; Apache: SSLUseStapling on) to fetch and cache OCSP responses. If the OCSP responder is unreachable, the server falls back to a handshake without stapling. Monitor the OCSP fetch success rate.
Häufige Fragen
- OCSP vs CRL — what is the difference?
- CRL (Certificate Revocation List) is a list of all revoked serial numbers — it can be large and slow to download. OCSP is a real-time query for a single certificate's status. OCSP stapling combines the best of both: real-time status without the client round-trip.
- What if the OCSP responder is down?
- The server cannot staple a response and falls back to a normal handshake. The client may then check OCSP itself (with a timeout) or accept the certificate (soft-fail). This is a weakness of OCSP — consider OCSP Must-Staple for critical certificates.