To harden our IBAN servers against intrusion, we have taken these measures:
Our servers are equipped with RAID-1 hard drives, which means that hard drive failures do not lead to an interruption of service or loss of data, unless both drives in a server fail at the same time (or at least in short enough succession for us to not yet have repaired the first drive when the second one fails).
We back up data daily, so even in case an entire server is destroyed, the loss of data is limited to the changes from the last 24 hours.
We use multiple servers which run 24 hours a day in different computer centers (some of them in different German cities). Another server monitors the reachability of the IBAN servers and redirects your requests to a backup server within minutes in case the main server does not respond. More details...