HTTP Web Server Load balancing for Web Applications OWA IIS Apache

HTTP Load Balancer – Web Servers

Web servers are at the core of almost every activity that people use the Internet for. Whether accessing corporate information, checking work or personal email, staying in touch with colleagues, friends, family, via social media, there is likely to be a web server in the path from user to service. Even in today’s increasingly mobile centric world, web servers will be doing the work to populate web views that are wrapped up in mobile applications.

Given the diverse services that use web servers, and the unpredictability of the load that can be placed upon them, it can be hard to design and implement a robust web server infrastructure. Deploying load balancers between web servers and the clients that are using them makes the design, delivery, and management of web server infrastructure easier.

A load balancer is made up of a suite of software tools that work in concert. KEMP LoadMaster load balancers can be deployed as dedicated devices with the software preinstalled. The LoadMaster software can also be deployed on existing server hardware, or as a virtual server on VMware vSphere, Microsoft Hyper-V, Microsoft Azure, or other cloud services. Think of the KEMP LoadMaster load balancer as a system of network optimisation tools that deliver:

  • HTTP Reverse Proxy
  • A number of traffic and routing optimisation algorithms
  • Image caching (reducing web server load)
  • Content caching
  • Compression
  • Content Switching and Rewriting
  • SSL Encryption/Decryption (further reducing server load)
  • Single Sign On (preventing users having to login when being switched between servers)
  • GEO and DNS failover
  • Cookie Persistence

Placing load balancers between web servers and users means that the load balancers become the ones that deal with access requests. The public addresses associated with service domain names point to the load balancers.

Figure 1 - HTTP Load Balancer and Reverse Proxy

The load balancers act as Reverse Proxies to handle client requests for access to the web servers. The load balancers query the back-end web servers instead of the clients interacting with them directly. This helps secure the back-end servers from attack, as the only network connections they need to have opened are from the secure LoadMaster servers.

Sitting where they do in the logical chain between clients and the web servers, load balancers are ideally placed to help secure and protect the back-end content servers. KEMP LoadMaster includes a comprehensive Web Application Firewall Pack. This works alongside traditional network firewall provision to greatly enhance the security of the network border between Internet and web servers.

Also in relation to network security, the KEMP LoadMaster load balancers are an ideal replacement for the discontinued Microsoft Forefront Threat Management Gateway (TMG) product. Deploying the KEMP Edge Security Pack on LoadMaster provides a supported replacement for TMG.

If you have web servers then deploying KEMP LoadMaster load balancers will greatly enhance the performance, security, resilience and manageability of the service you are providing.

In addition to these technical benefits your Search Engine Optimisation (SEO) footprint on the web will be improved and easier to manage and monitor. Multiple back-end services and servers will be aggregated for search engines and other web crawlers behind the unified web presence delivered by the front-end KEMP LoadMaster load balancers.