The Red Hat Network (RHN Classic) CA SSL certificate is distributed with products that connect to the Red Hat Network, such as Red Hat Enterprise Linux, and is used to verify the product's secure connection to the service.
The CA certificate contained in older rhn client packages (those prior to erratas listed on https://access.redhat.com/site/solutions/353033) expires in August 2013 and will result in connection failures after RHN Classic renews the certificate on August 12th, 2013.
Please make sure your systems running Red Hat Enterprise Linux versions 5 or earlier  have updated rhn client packages which contain the new certificate in order to continue to connect to the Red Hat Network securely after August 12, 2013 - refer to this solution for affected rhn client packages/versions and for instructions on updating the packages.
If the CA certificate is not updated, your Red Hat Enterprise Linux systems will no longer be able to securely connect to RHN Classic and receive updates. Systems running Red Hat Enterprise Linux 6 or above, and/or using Red Hat Subscription Management, are not impacted.
 This also includes Red Hat Satellite and Proxy servers themselves in connected mode, and client systems in RHEL client->Red Hat Proxy Server->RHN Classic configurations.