When we recently asked Citrix about a XenApp server on Linux this is the response that we got:

“To answer your question, XenApp does not currently run on Linux. From its original development, XenApp has always been focused on delivering Windows-based applications, which have and continue to represent the majority of the applications that our enterprise customers use. We will continue to evaluate customer needs but we don’t currently have any plans to extend XenApp to the Linux platform.”

To provide the same functionality of XenApp on Solaris with the XenApp product for Windows a customer must:

• Purchase Microsoft Windows Terminal Server 2003 or 2008.
• Purchase Terminal Server Client Access Licenses, CALS, for each user.
• Purchase Citrix XenApp for Windows.
• Purchase Citrix concurrent user licenses.
• Acquire a X-Windows Display Server product for Windows Terminal Server.
  • Free versions such as: Cygwin/X, Xming and WeirdX
  • Commercial versions such as: Exceed, MKS X/Server, MI/X, WinaXe and X-Win32

If Citrix does not address Linux, then I suspect they will have a number of customers switch to other products. Most of the chip design and manufacturing companies use tools that run on Linux and utilize X-Windows. Many of them use Citrix XenApp, Metaframe or Presentation Manager for Unix. The chip test and assembly suppliers that we deal with use a Citrix XenApp Unix product as well. All of these companies that I deal with run their XenApp server product on Solaris Sparc.

Unless Citrix has changes their licensing; “Why would I replace my XenApp Solaris product with XenApp on Windows?”. To run XenApp on Windows, you must purchase both Citrix and Windows Terminal Services Licenses. The functionality in Windows Terminal Server 2008 is much improved. Given the improvements in Windows 2008, I will be hard pressed to convince my management that they should spend the additional $$$ for Citrix. Instead, we may consider using the Citrix $$$ to purchase X-Windows display software for Windows. Although, my 1^st evaluation might be the free open source Xming software.

A promising replacement option might have been the Sun Secure Global Desktop. However, with the Oracle acquisition, I’ll be waiting to see what Oracle does with this product before I give it any serious consideration. I did a thorough technical evaluation of this product prior to version 4.4. The product performed well and was secure. The AIP protocol used competed well with Citrix’s ICA protocol. However, it would not integrate with our standard PAM security mechanisms that are in place. This was a “show-stopper” and quite a surprise since PAM is the standard method to integrate authentication schemes in UNIX. According to the Sun Secure Global Desktop 4.5 Administration Guide, this limitation appears to have been eliminated in the 4.5 version.

Aother product that I will re-examine is Go-Global for UNIX. They have support for Red Hat Enterprise Linux and SUSE Linux.

Some of you may be asking; “why not use VNC?”. Basically, VNC is insecure and the VNC networking protocol does not perform as well as the Citrix ICA protocol. I can use a network sniffer and extract account ids and passwords from VNC traffic. There are versions of VNC, like RealVNC , which to some extent address the security issues. However, I have users on the other side of the world using CAD tools via Citrix XenApp. I do not obtain similar network performance from VNC.

To be fair, Solaris will not go away tomorrow. However, given all of the products and technologies that Sun was supporting with considerable losses and with the profits the Oracle has promised, something must give. I quit believing in the “tooth fairy” a long time ago. To me, this means that I must be thinking about this now. In addition to considering the use of Windows 2008 Terminal Server and an X-Windows Display server, there will be a number of other Remote Desktop Software products to consider.