ok, so according to the presentation a netscaler is:
a load balancer
a reverse proxy
a SSO gateway
a (W)AF (web application firewall)
now first two points can be obtained by haproxy/ngnix
point 3 can be obtained -just googled- for web apps by naxsi + nginx or modsec + nginx/apache.
also point 3 for non web apps can maybe obtained via these softwares (wiki)
I miss point 2 an - with a bit of effort - I have my free open netscaler 😛