NetScaler

Citrix NetScaler is an “application delivery controller” with four main functions.

Routing

It is helpful to think of NetScaler providing front doors and back doors. A user’s request for a webpage will come in through a front door, and will go out through a back door to the actual website which holds the requested webpage.

The corporate website at www.kleenheat.com.au will have a public front door, available to anyone on the internet, and its page requests will go to the back door connected to the public website application.

My Kleenheat at my.kleenheat.com.au will have a public front door, available to anyone on the internet, and its page requests will go to the back door connected to the combined CSI/My Kleenheat website application.

Customer Service screens at csi.kleenheat.com.au will have a private front door, available only to someone on our internet network, including a customer service officer at hone connected to our virtual private network (VPN), and its page requests will go to the back door connected to the combined CSI/My Kleenheat website application.

It is through NetScaler’s public front door for my.kleenheat.com.au, and the private front door for csi.kleenheat.com.au, that we can deliver both a public My Kleenheat website and a private CSI website, even though they are actually the same website application.

Application Firewall

Any page request which comes through NetScaler must pass through a large number of security checks which guard against common hacking attempts and problematic requests.

The application firewall can be different across front doors, so that a public front door may have a more stringent set of security checks than applies to a private front door.

Load Balancing

If any website starts receiving more users than it can handle, we can create a second instance of that website and have NetScaler distribute users between the two. Presently we do not experience sufficient load to require balancing between multiple instances of a website.

Caching

NetScaler can cache pages and assets. We typically use NetScaler to cache assets such as style sheets, script files, and images, but do not use NetScaler to cache pages.

Next section: Websites