The IBAN calculator is hosted at several Hetzner computer centers and at Manitu. Our computer center providers promise a network availability of 99 %. We alleviate the consequences of hard drive failures by using a RAID-1 setup in every server.
To surpass the 99% availability rate, we use an automatic DNS-based failover mechanism.
If ssl.ibanrechner.de becomes unavailable, the DNS record for ssl.ibanrechner.de is automatically pointed to the server normally known as bak1.iban-bic.com. This server runs at a different computer center thus it is unlikely to fail at the same time.
The name servers and the monitoring service which initiates failovers are all located outside the computer centers which host our IBAN servers. This means that the failover mechanism runs independently of the servers whose failures it deals with.
If you use a firewall, please open it for the following 3 IP addresses to make sure you actually benefit from our automatic failover mechanism: