Back in March I asked if 2010 was going to be the year that we would run out of IPv4 addresses on the Internet. And yes, it is still on course to happen, if not this year, then next, as it is increasingly difficult for ISPs to get their hands on tranches of IP addresses. 

“Are Citrix products ready for a transition to IPv6?” is a good next question to ask, and the answer is YES, for the most part.

The most affected products are those that are directly internet facing, particularly NetScaler and Access Gateway. 


NetScaler has supported IPv6 features since 2007. But with version 9.0, support for IPv6 was enhanced, allowing IPv6 communication all the way back to the application servers in the data center. NetScaler 9.2 provides further improvements for mixed IPv4 / IPv6 environments. These are the types of environments we will see a lot of in the next few years as we are transitioning from purely IPv4 to predominantly IPv6. You can hide your IPv4 servers behind NetScaler and give them IPv6 internet addresses. Conversely, you can place IPv6 servers behind NetScaler with IPv4 public addresses. Being able to give your sites public IPv6 addresses without the concommitant cost of renumbering your internal network is going to be agreat help to many enterprises

Access Gateway

Access Gateway Enterprise Edition (AGEE) has supported IPv6 for some time with the current level of support illustrated in the following possible scenarios. Additional scenarios will be supported going forward including those where both the client-side and corporate network are configured with IPv6.

Client-side Network Corporate Network What is supported today
IPV4 IPV4 Supported
IPV4 IPV6 Auth servers in IPV6 network supported
IPV6 IPV4 XA/XD servers in IPV4 network – Supported

Citrix will continue to evolve the Access Gateway strategy, vision, and roadmap to address simple, secure, and fast application access and delivery over both IPv4 and the growing number of IPv6 networks.

Other products

As the transition to IPv6 is most urgent for internet facing equipment that requires a unique IP address, there is less immediate demand for IPv6 support in XenApp, XenDesktop and Branch Repeater.

Today, both XenDesktop and XenApp support IPv6 in a proxy mode behind Access Gateway. As US federal government agencies are beginning to mandate IPv6 support, there are plans afoot to support a direct IPv6 connection from Receiver to the desktop or the application and to add full IPv6 support to the management infrastructure.

Branch Repeaters are typically installed inside the corporate network to speed up communications between enterprise branches or datacenters. Their operations are generally internal and not exposed to the wider internet. That said, there are plans to begin supporting IPv6 in the future as field demand dictates.