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Leading Supplier Search Website “Wer liefert was” (WLW) Relies on F5

Wer liefert was” (WLW) is the leading B2B supplier search website in Germany, Austria, and Switzerland. Month by month, 1.6 million decision makers looking to place orders for their purchasing departments go to,, and to review more than 500,000 manufacturers, service providers, wholesalers, and resellers.

WLW wanted to replace its outdated load balancers with a high performing and secure Application Delivery Controller (ADC). The company chose F5 BIG-IP Local Traffic Manager ADC. The F5 solution provides WLW with firewall and user identification capabilities plus the ability to offer fast, 24/7 availability of its search engine to WLW customers.

Business Challenges


Headquartered in Hamburg, Germany, WLW employs 200 people. The company was founded in 1932 and was the first distributor of printed reference listings for commercial buyers. WLW has been offering its services exclusively online since 1995.

A failure of satellite systems would have had virtually no effect on WLW productivity a few years ago, but nowadays these systems have to be available around the clock. Essential for ensuring the availability of the search engine, Application Delivery Controllers are a crucial building block for business success.

The company’s previous load balancers had come to the end of their life cycle. WLW decided to replace them with Application Delivery Controllers for an extendible platform. The change would afford an ideal opportunity to eliminate the weaknesses of the old system. “One big problem was that the old load balancers didn’t have adequate firewall functionalities,” recalls Jörn Oltmann, Manager of Site Operations & Services at WLW. He adds: “And we nearly always failed when we tried synchronizing configuration of the load balancers.”

The range of settings available in the administrator GUI had also proved insufficient. WLW was not able to run scripts of its own on the load balancers and the possibilities for logging were severely restricted. The officers at WLW also grumbled that they were unable to use cookies to identify online clients, had no access to port forwarding functions, and could not schedule SSL encryption on the load balancers.

“We place a high-performance, high-availability supplier search engine at the disposal of users and clients. Within the company too, our IT requirements are ultra-high. … So, we rely on solutions from F5…” Jörn Oltmann, Manager of Site Operations & Services, WL



WLW set the bar high for the new solution.  The main criteria were the functionality of load balancing and straightforward administration. Product Development needed the new functionalities as soon as possible, so WLW put its faith in the expertise of its systems support partner.

WLW operates a data centre in which at this time, about 55 virtual servers are addressed through BIG-IP Local Traffic Manager (LTM). There are some 120 virtual servers configured on the BIG-IP device. The search engine consists of numerous servers using internal and external services. The primary application is the proprietary search engine, which is based on Ruby on Rails and CouchDB. The SAP Web Dynpro customer portal takes the second slot. Internal services like the DMZ also access functions of the F5 solution.

“Firstly, we wanted a solution that would be better than what we had beforehand.  But secondly, we were looking for a product that would be as open as possible instead of a black box. It had to be an end-to-end approach that could deal with the challenges of today and remain open for those of the future as well. Once we had taken the decision to go with F5, we moved straight on to totally smooth installation of the F5 solution jointly with our chosen partner,” says Oltmann. “BIG-IP LTM is now the centrepiece in our IP landscape, and it carries the data traffic of all services inbound and outbound. The BIG-IP device also handles scheduling for all SSL traffic, and it employs iRules to control access to internal services for our people in the field.”



Oltmann is very satisfied with support and with the solution itself. “Problems that arose in productive operation were dealt with quickly and effectively by F5. As far as we are concerned, the biggest benefits are straightforward administration and the iRules, which we use primarily to control access to the virtual servers.”

A complete new F5 system is set up within approximately 30 to 45 minutes. It takes only a few minutes to set up a new virtual server. The WLW applications are configured on the F5 BIG-IP LTM 3600 device and then run without any problem. Manual post- configuration tweaking is necessary only rarely.

Oltmann is also positive in his assessment of iRules: “Without the iRules set for rights management, we would have to control access to the virtual servers through server configuration. That was really a pain in the past, because configuring several servers took time. With the F5 BIG-IP LTM 3600 device, everything is under central control, so it is as quick as you would expect it to be.”

In the opinion of Oltmann, the benefits of the F5 solution extend over several sectors. The users of the search engine can be tracked more effectively, which means they can be offered better services. The F5 solution has also cut maintenance times and reduced the likelihood of error in administration.

Oltmann explains, “We place a high- performance, high-availability supplier search engine at the disposal of users and clients. Within the company too, our IT requirements are ultra-high. You could well say that in terms of technology, high availability and speed are the basic prerequisites for our business. If our IT people failed to deliver, it would pull the carpet right out from under all our other specialist departments. So, we rely on solutions from F5 to establish the firm basis we need for our IT.”  In particular, there is now much less risk of administration disrupting availability.  Tasks that WLW formerly had to schedule for nights can now be wrapped up during the day. As a result, employee workload and costs can be reduced. The F5 solution, moreover, replaces three software load balancers, so there are fewer systems requiring support. Reducing complexity in this way streamlines and accelerates administrative processes and helps cut costs.

“Now that we have the F5 BIG-IP LTM 3600 device in place, we need considerably less time for maintenance of the load balancers.  So, we free up resources formerly tied up in administration. It is not easy to put a precise figure on the amount of time we save, but our best estimate would be a high one- figure percentage,” reckons Oltmann. “A moment of non-availability translates into a loss of image for WLW. With clustering, partitioning, and the different boot devices in the F5 BIG-IP LTM 3600 device, we now have virtually no downtime whatsoever.”

The IT agility achieved with the F5 solution makes synergy projects easier to implement.  Changes mapping business developments in the network infrastructure are easier to effect. Another benefit is that tasks can be shifted from web development to system administration, and time-to-market is reduced. All these benefits from the F5 solution contribute to the overall business success of “Wer liefert was,” WLW.