Using Public-Key Infrastructure (PKI) in Your Network
The ExtremeXOS implementation of public-key infrastructure (PKI) supports
the secure authentication of Syslog server and SSH client to an Extreme Networks XOS device using
an X.509 certificate. Below are primary aspects of a PKI configuration (for more information
about each command listed in this topic, see
ExtremeXOS 22.3 Command Reference Guide):
- Trusted CA—The X509v3 certificates of Certificate Authority (CA) should
be downloaded using the CLI: download ssl ipaddress
certificate {ssl-cert | trusted-ca | ocsp-signature-ca} cert_file using the trusted-ca option. The CA
certificate must satisfy the following criteria to successfully download:
- Basic constraints: CA = true
- Key usage must contain: KeyCertSign
- Peer Certificate—X509v3 certificate of the peer, signed by one of the
above trusted CAs. The following criteria must be met for successful authentication:
- Syslog server certificate: Extended key usage must contain ‘Server
Authentication‘
- SSH Client certificate:
- Common name (CN) of the certificate subject must be same as the
username with which SSH session is tried out.
- Extended key usage must contain ‘Client Authentication.‘
- OCSP—Online Certificate Status Protocol used to find the revocation
status of the peer certificate on the following scenario:
- Syslog server certificate‘s OCSP status is identified when a TLS
session is to be established with the Syslog server. Only if the OCSP status is GOOD is the
session established.
- SSH Client certificate‘s OCSP status is identified as part of
authentication. Only if the OCSP status is GOOD is the session established.
Note
OCSP processes intermediate CA certificates
iteratively, one by one.
The OCSP Server‘s address must be
configured in the Authority Information Access (AIA) of the peer certificate. Otherwise, the
PKI authentication fails. The supported OCSP responder models are: common issuer model,
delegated trusted responder model, trusted responder model.
- OCSP Signature CA—To support Trusted Responder Model (TRM) of OCSP, the
X509v3 certificate of the OCSP responder should be downloaded using the CLI: download ssl ipaddress
certificate {ssl-cert | trusted-ca | ocsp-signature-ca} cert_file using the ocsp-signature-ca option. The OCSP
signature CA is only required for TRM; it is not used for DTM and common issuer. This
certificate must contain a trusted use extension that permits OCSP signing. A “trusted use
extension” can be appended to a certificate using OpenSSL.
The following
example appends a trusted use extension specifying an original file and the trusted file:
ocsp-sig-ca.pem is the original
certificate file and the output file trusted-ocsp-sig-ca.pem is the trusted file: % openssl x509 -in ocsp-sig-ca.pem
-addtrust OCSPSigning -out trusted-ocspsig- ca.pem
The following is
an example of an original certificate followed by the OpenSSL command output trusted
certificate:
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
-----BEGIN TRUSTED CERTIFICATE-----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-----END TRUSTED CERTIFICATE-----
- ExtremeXOS X509v3 certificate—The certificate of the ExtremeXOS device.
This is shared to the Syslog server to perform authentication there. Use the commands: download ssl ipaddress
certificate {ssl-cert | trusted-ca | ocsp-signature-ca} cert_file with the ssl-cert option, and download ssl ipaddress privkey key_file
.