Explanation
To implement DNSSEC, no additional changes are needed to applications or their code because the integrity checks are all performed at the system level.

Best practices and industry standards dictate that a BCDR solution should be tested at least once a year, though specific regulatory requirements may dictate more regular testing. The BCDR plan should also be tested whenever a major modification to a system occurs.

Explanation
Any application can be a possible target of denial-of-service (DoS) attacks. From the application side, the developers should minimize how many operations are performed for non-authenticated users. This will keep the application running as quickly as possible and using the least amount of system resources to help minimize the impact of any such attacks.