3 Ways to Optimize Microsoft IIS with an Application Delivery Controller

September 10, 2019
3 min read time
3 Ways to Optimize Microsoft IIS with an Application Delivery Controller

Microsoft’s Internet Information Services (IIS) is one of the world’s most popular web servers for hosting just about anything on the web. A big part of the attraction, especially for companies that employ DevOps methodologies, is that it’s compatible with all Windows services and runs in Windows environments, which makes it easier to integrate and support business-critical apps. But IIS web servers can also put excessive strain on computing resources and slow down website response times.

Whatever the size or type of your business – whether it’s financial services, IT services, ecommerce, retail or healthcare – slow response times are bad for business. Consumers are notoriously quick to abandon websites with slow-loading pages, and the knock-on effects are lower sales and a tarnished brand. If your website is suddenly slow and you notice you’re burning through more compute power than you expected to, then your IIS web servers will benefit from an Application Delivery Controller (ADC) providing load balancing and web acceleration.

Load balancing can prevent a single IIS server from being overloaded and ensure your system stays up and running even under intense load – i.e., during periods of high demand for your products and services, or unexpected events that cause a surge in visits to your site. Web acceleration techniques can offload common tasks and speed up page load, further reducing the load on your IIS servers.


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We’ve identified three common challenges that businesses encounter with Microsoft IIS and how the right ADC can help to resolve them.

1. HTTP/S Session Persistence

Websites with thousands or even millions of visitors must handle huge volumes of traffic in the most efficient way possible. Part of that efficiency is achieved through session persistence. That is, a visitor’s interactions with a website are sent to the same server for their entire session on the site. For example, when a customer visits an ecommerce site like Amazon, that person’s requests would be directed to the same server. Without HTTP/S session persistence, requests would be sent to different servers and it would take much longer for users to complete transactions.

With an ADC, there are many ways of keeping track of which IIS server a user is logged into so that the user is consistently sent back to that server. An additional technique is cookie insertion, whereby the ADC dynamically modifies cookies on the user’s browser so that they can be identified no matter where they go on the site.

2. Page Requests and Load Speed

IIS uses a lot of compute resources, which drives up capital and operating costs if you’re continually having to add more capacity to maintain system performance and high availability. Also, the web page content that IIS serves up for each request is often overly complex and large, which slows down response times.

An ADC with web acceleration features will automatically optimize web pages to increase response times and offload backend servers to free up compute resources. Web acceleration techniques include minifying and combining JavaScript and stylesheets, and recoding images so that they are smaller and load faster. The result is faster page load and rendering times. And by caching content, fewer requests actually go to the IIS web server, which delivers a further speed boost.

3. SSL Handling

HTTP/S uses Secure Sockets Layer (SSL) to encrypt and secure communications between a user’s browser and the IIS web server. Web sites receive security ratings based on how well they have implemented and configured SSL. But SSL can put a strain on CPU resources, which makes handling SSL traffic highly inefficient.

An ADC can offload SSL traffic from your IIS web servers to minimize the strain on compute resources and enable SSL certificates to be centrally managed. This will ensure your web site is always operating in a secure environment and will help you to achieve an A+ security rating, which will drive higher search engine results and better protect your customers.


Snapt is a modern software ADC that includes a Load Balancer, Web Accelerator and Web Application Firewall. And as a Microsoft partner, Snapt is designed and pre-configured to load balance IIS, as well as other services including Microsoft Exchange and Remote Desktop (RDP).

Try Snapt ADC for free today to find out why Snapt is the ideal choice for Microsoft IIS web servers.

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