Success Story TechniSat

We started with a kind of preliminary project in which we worked out possible scenarios and used them to create a detailed concept for the customer. concept for the customer. This had several advantages: We were able to familiarize ourselves with the customer's environment and existing system landscape in advance and subsequently provide an even more qualified cost and effort estimate as well as a technically sound offer.technically sound offer.

The customer had an Exchange cluster with a total of five servers and an internal structure of various applications and scripts that had grown over the years and interacted with the email environment. The aim was to reduce the administration effort for IT and to migrate Microsoft Exchange Server to the latest version - which had to be done in two stages due to the complex technical circumstances. As part of the migration, we designed and implemented a system consisting of just two machines.

The customer wanted to continue to operate its Exchange server in its own data center. Nevertheless, employees were to be given access to certain cloud services such as Microsoft Teams so that they could, for example, access their calendar data via Teams - even if this is located on the local Exchange server.

For additional protection against potential attacks, we use so-called reverse proxies. These receive all requests from outside, examine them and only then pass them on to the Exchange servers. A load balancer acts as a reverse proxy here, distributing the data traffic between the two servers. If one of them fails, all requests are forwarded to the other. To ensure that this distribution computer does not become a bottleneck and paralyze the entire environment in the event of a failure, we have also designed it redundantly. This means that there are two load balancers for all external requests and another two for all internal requests. This solution not only guarantees maximum reliability, but also allows even more targeted security measures than a shared environment thanks to the separation of internal and external systems.

One challenge was to ensure that all existing applications would also work in the new environment, including an external archiving solution for the long-term storage of documents and emails as well as a third-party anti-spam solution, which - unlike the new email server - was located in a so-called demilitarized zone (DMZ).

Another challenge was connecting the customer's various locations and companies with regard to the Microsoft Active Directory: while the Exchange servers at the customer's main location serve as the central email server for all companies, the directory services and servers are organized decentrally. Nevertheless, the e-mail servers must be able to communicate and exchange data with them.

TechniSat also has a relatively differentiated IT system. This means that there are different contacts for different topics that had to be brought together. On the one hand, this was positive because we were able to coordinate things at a high technical level. But it also means that you always have to keep everyone involved in the project up to date. There was a project manager on both our side and the customer's side, who together formed the project steering committee and ensured constant communication with everyone involved in the project.

Thanks to the upstream project, we were able to estimate the workload very well and ultimately meet it exactly on time. We implemented the migration project itself within four weeks - and stayed within the planned budget.