Cisco Cisco Expressway Maintenance Manual
Note that if a certificate authority's CRL expires, all certificates issued by that CA will be treated as revoked.
Configuring revocation checking for SIP TLS connections
You must also configure how certificate revocation checking is managed for SIP TLS connections.
1. Go to
Configuration > SIP
.
2. Scroll down to the
Certificate revocation checking
section and configure the settings accordingly:
Field
Description
Usage tips
Certificate
revocation
checking
mode
revocation
checking
mode
Controls whether revocation checking is performed for
certificates exchanged during SIP TLS connection
establishment.
certificates exchanged during SIP TLS connection
establishment.
We recommend that revocation
checking is enabled.
checking is enabled.
Use OCSP
Controls whether the Online Certificate Status Protocol
(OCSP) may be used to perform certificate revocation
checking.
(OCSP) may be used to perform certificate revocation
checking.
To use OCSP, the X.509 certificate
to be checked must contain an
OCSP responder URI.
to be checked must contain an
OCSP responder URI.
Use CRLs
Controls whether Certificate Revocation Lists (CRLs)
are used to perform certificate revocation checking.
are used to perform certificate revocation checking.
CRLs can be used if the certificate
does not support OCSP.
does not support OCSP.
CRLs can be loaded manually
onto the Expressway,
downloaded automatically from
preconfigured URIs (see
onto the Expressway,
downloaded automatically from
preconfigured URIs (see
downloaded automatically from a
CRL distribution point (CDP) URI
contained in the X.509 certificate.
CRL distribution point (CDP) URI
contained in the X.509 certificate.
Allow CRL
downloads
from CDPs
downloads
from CDPs
Controls whether the download of CRLs from the CDP
URIs contained in X.509 certificates is allowed.
URIs contained in X.509 certificates is allowed.
Fallback
behavior
behavior
Controls the revocation checking behavior if the
revocation status cannot be established, for example if
the revocation source cannot be contacted.
revocation status cannot be established, for example if
the revocation source cannot be contacted.
Treat as revoked: treat the certificate as revoked (and
thus do not allow the TLS connection).
thus do not allow the TLS connection).
Treat as not revoked: treat the certificate as not
revoked.
revoked.
Default: Treat as not revoked
Treat as not revoked ensures that
your system continues to operate
in a normal manner if the
revocation source cannot be
contacted, however it does
potentially mean that revoked
certificates will be accepted.
your system continues to operate
in a normal manner if the
revocation source cannot be
contacted, however it does
potentially mean that revoked
certificates will be accepted.
Configuring certificate-based authentication
The
Certificate-based authentication configuration
page (
Maintenance > Security certificates >
Certificate-based authentication configuration
) is used to configure how the Expressway retrieves
authorization credentials (the username) from a client browser's certificate.
page) has been
set to Certificate-based authentication. This setting means that the standard login mechanism is no longer
available and that administrators can log in only if they present a valid browser certificate — typically
available and that administrators can log in only if they present a valid browser certificate — typically
Cisco Expressway Administrator Guide (X8.2)
Page 213 of 378
Maintenance
About security certificates