Is this distribution free like Fedora,Centos,etc? I have installed Firefox on Oracle Unbreakable Linux and it open a webpage when it ask me for get a new CA certificate. The CA certificate Require an oracle login(free) and a customer support identifier (CSI) which is not free.
To quote the Oracle Linux Premier Support page:
All Oracle Linux software is provided for free and can be downloaded from Oracle Software Delivery Cloud.
That seems to answer your question fairly directly. Some features (such as Ksplice) require a support contract, but the cost model is similar to that of Solaris: you pay for a support contract (and possibly features), not for the software itself.
As to your certificate issue, the ULN updated to SHA-256 at the end of 2016. The alert message appears to be static text on the homepage, and does not necessarily reflect the status of your system. If you do not get further errors regarding the certificate, then the one on your system is up to date and there is nothing more you need to do.
If you do find that your system has the old certificate, the FAQ includes a sequence of steps to update to the new one:
# cp /usr/share/rhn/ULN-CA-CERT /usr/share/rhn/ULN-CA-CERT.old # wget https://linux-update.oracle.com/rpms/ULN-CA-CERT.sha2 # cp ULN-CA-CERT.sha2 /usr/share/rhn/ULN-CA-CERT
I have not verified that these are the correct paths for recent Oracle Linux installations, but I have verified that the
wget portion works even on non-Oracle systems.