Kemp Technologies LoadMaster 2500

Layer 4 inspection can maintain persistent connections where the appliance uses source and destination IP addresses to ensure a specific client is always directed to the same server. Layer 7 inspection takes this up a notch as you can use actual content to set up persistent connections along with features including session IDs, URLs and cookies. In a basic farm you'll probably have a bunch of servers providing identical services but for environments where farms comprise servers offering different content you can include rules. These inspect HTTP content and are used to direct a host to the correct server. Even SSL acceleration is on the menu allowing the appliance to reduce the workload on the farm by terminating encrypted connections and sending unencrypted traffic to the servers.

For testing we deployed Windows Server 2003 web servers on the LAN with some also running web mail and FTP services. We had no problems linking our real servers to virtual services and our test clients only had to point their browsers at the new virtual IP address where the requested service was loaded as normal. Standard web services continued unabated and users were none the wiser that their web mail and FTP requests were being handled by the appliance. Along with general web access we tested using the web mail components in Ipswitch's iMail Server 8 and we could also access our FTP services via the LoadMaster using tools such as the excellent FileZilla utility. For the latter we declared two real servers both running Windows FTP services with identical file locations and configured them in a single virtual service. We used two clients to access and download a range of files and from the LoadMaster statistics interface we could see the load being shared across both members of the virtual service.

For the price the LoadMaster 2500 is offering a remarkable range of features. Typical competition comes from Barracuda's Load Balancer appliances where, although the entry level 240 costs less, it pales into insignificance as it doesn't support Layer 7 inspection or SSL acceleration. The 440 does support these features but is poor value as its hardware spec is only good enough for a paltry 200 TPS for SSL acceleration and its IPS services will incur a yearly subscription fee. No, if you want a dedicated low-cost server load balancing appliance that doesn't sacrifice on features then check out the LoadMaster series.