Overview:

VMware horizon view security server now the Unified Access Gateway is the secure gateway it will enable to access the VDI from external network (public ISP). Horizon standard advanced enterprise license is required for UAG. UAG improved blast extreme protocol this future is not available in windows based security server. UAG placed into the DMZ network. UAG packaged as an OVF. Its Linux appliance based on SUSE enterprise Linux so it’s improves security.

http://partnerweb.vmware.com/comp_guide2/sim/interop_matrix.php#interop&260=&326=

Hope this will be informative for you Thanks for Reading !