S 6.101 Data backup when using VoIP

Initiation responsibility: IT Security Officer, Head of IT

Implementation responsibility: Administrator

To be able to restore VoIP operations quickly in case of a faulty configuration or a failure that can only be fixed by replacing a component, regularly backups of all important configuration files must be made. The procedure mentioned in module S 1.4 Data backup policy must be used for data backup as a matter of principle. The scope of the files to be backed up are determined based on the VoIP components used. The data to be backed up includes, among other data:

• all VoIP-specific configuration settings,
• higher-level configuration settings such as IP addresses, passwords, and all relevant operating system configurations used,
• log data, and
• data entered by the users themselves, e.g. in personal telephone books.

These configuration settings must be backed up regularly. A backup should also be made before and after making any change to the configuration. It must be ensured in this case that several versions (generations) of the files backed up are maintained. An incorrect configuration can often be fixed by restoring the last version of the configuration file backed up.

It must be noted that it may be impossible to restore the existing configuration files after switching to a new version release. For example, if a hardware device that uses a newer or an older release fails, it may be impossible to restore the existing configuration files directly from a backup. For this reason, the current manufacturer information, for example in the changelog files, must be examined and taken into account when a component is replaced. If the configuration files need to be adapted to the new version release, then both the old configuration files as well as the new configuration files must be backed up. If there are problems with the newer release, it is then possible to switch back to an older, possibly more stable version later on.

The data is to be backed up on IT systems and media that are independent from the IT systems and media used for operation, for example tape drives, CD-RWs, or other IT systems. If this data is transmitted to another system over a network, encryption of the data or transmission of the data over a separate administration network should be considered to protect it from eavesdropping and manipulation.

Recovery tests must be performed regularly to check if the backups can be restored (see also S 6.41 Training data reconstruction for more information on this subject).

Review questions:

• Is there a regulation governing the definition of content and scope of the data backup?
• Are different versions of configurations and changes documented in a comprehensible manner?
• Is the nature of the backup files of the configuration such that they can be reconstructed and reversed in case of a conflict?
• Are malfunction and emergency procedures tested regularly?