Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.112.0P1 - Page 1099

Syslog over TLS, Online Certificate Status Protocol (OSCP), Configuring OCSP setting on CA

Page 1099 highlights

TLS_ECDH_RSA_WITH_AES_256_CBC_SHA TLS_ECDH_RSA_WITH_AES_128_CBC_SHA TLS_DH_RSA_WITH_AES_256_CBC_SHA TLS_DH_RSA_WITH_AES_128_CBC_SHA TLS compression is disabled by default. TLS session resumption is also supported to reduce processor and traffic overhead due to public key cryptographic operations and handshake traffic. However, the maximum time allowed for a TLS session to resume without repeating the TLS authentication or handshake process is configurable with a default of 1 hour. You can also disable session resumption. Syslog over TLS Syslog over TLS mandates that a client certificate must be presented, to ensure that all Syslog entries written to the server are from a trusted client. Online Certificate Status Protocol (OSCP) Use the Online Certificate Status Protocol (OSCP) to obtain the revocation status of a X.509v3 certificate. A device or a Certificate Authority (CAs) can check the status of a X.509v3 certificate by sending an OCSP request to an OCSP server or responder. An OCSP responder, a server typically run by the certificate issuer, returns a signed response signifying that the certificate specified in the request is 'good', 'revoked', or 'unknown'. The OCSP response indicates whether the presented certificate is valid. OCSP provides a way for Certificate Authorities to revoke signed certificates before the expiration date. In a CA certificate, OCSP Responder information is specified in the authorityInfoAccess extension. A CA can verify the revocation status of a certificate with multiple OCSP responders. When multiple OCSP responders exist, you can configure the order or preference the CA takes while contacting various OCSP responders for verification. Upon receiving a presented certificate, the system sends an OCSP request to an OCSP responder through HTTP. The system then verifies the OCSP response using either a trusted public key or the OCSP responder's own self-signed certificate. This self-signed certificate installs on the device's trusted location even before an OCSP request is made. The system accepts or rejects the presented certificate based on the OCSP response. In a scenario where all OCSP responders are unreachable, the switch accepts the certificate. This action is the default behavior. You can also configure an alternate system behavior when all OCSP responders are unreachable. However, the switch may become vulnerable to denial-of-service attack if you configure the system to deny the certificate when OCSP responders are not reachable. The system creates logs for the following events: • Failures to reach OCSP responders • Invalid OCSP responses-for example, cannot verify the signed response with an installed CA certificate. • Rejection of a certificate due to OCSP Configuring OCSP setting on CA You can configure the CA to contact multiple OCSP servers. To configure OCSP server for a CA, perform the following step: In the certificate mode, enter the following command: ocsp-server URL [nonce] [sign-requests] X.509v3 1099

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TLS_ECDH_RSA_WITH_AES_256_CBC_SHA
TLS_ECDH_RSA_WITH_AES_128_CBC_SHA
TLS_DH_RSA_WITH_AES_256_CBC_SHA
TLS_DH_RSA_WITH_AES_128_CBC_SHA
TLS compression is disabled by default. TLS session resumption is also supported to reduce processor and
traffic
overhead due to public
key cryptographic operations and handshake
traffic.
However, the maximum time allowed for a TLS session to resume without repeating
the TLS authentication or handshake process is
configurable
with a default of 1 hour. You can also disable session resumption.
Syslog over TLS
Syslog over TLS mandates that a client
certificate
must be presented, to ensure that all Syslog entries written to the server are from a
trusted client.
Online
Certificate
Status Protocol (OSCP)
Use the Online
Certificate
Status Protocol (OSCP) to obtain the revocation status of a X.509v3
certificate.
A device or a
Certificate
Authority (CAs) can check the status of a X.509v3
certificate
by sending an OCSP request to an OCSP server or
responder. An OCSP responder, a server typically run by the
certificate
issuer, returns a signed response signifying that the
certificate
specified
in the request is 'good', 'revoked', or 'unknown'. The OCSP response indicates whether the presented
certificate
is valid.
OCSP provides a way for
Certificate
Authorities to revoke signed
certificates
before the expiration date. In a CA
certificate,
OCSP
Responder information is
specified
in the authorityInfoAccess extension.
A CA can verify the revocation status of a
certificate
with multiple OCSP responders. When multiple OCSP responders exist, you can
configure
the order or preference the CA takes while contacting various OCSP responders for
verification.
Upon receiving a presented
certificate,
the system sends an OCSP request to an OCSP responder through HTTP. The system then
verifies
the OCSP response using either a trusted public key or the OCSP responder’s own self-signed
certificate.
This self-signed
certificate
installs on the device's trusted location even before an OCSP request is made. The system accepts or rejects the presented
certificate
based on the OCSP response.
In a scenario where all OCSP responders are unreachable, the switch accepts the
certificate.
This action is the default behavior. You can
also
configure
an alternate system behavior when all OCSP responders are unreachable. However, the switch may become vulnerable to
denial-of-service attack if you
configure
the system to deny the
certificate
when OCSP responders are not reachable.
The system creates logs for the following events:
Failures to reach OCSP responders
Invalid OCSP responses—for example, cannot verify the signed response with an installed CA
certificate.
Rejection of a
certificate
due to OCSP
Configuring
OCSP setting on CA
You can
configure
the CA to contact multiple OCSP servers.
To
configure
OCSP server for a CA, perform the following step:
In the
certificate
mode, enter the following command:
ocsp-server
URL
[nonce] [sign-requests]
X.509v3
1099