Potential Port Conflicts with Citrix License Server 11.6.1

A couple months back, I was working on a XenDesktop 3.0 installation.  The customer was having some issues with licensing, so my first thought was to upgrade the license server to the newest version – because historically that’s been the recommended first step in dealing with license issues.  In this case, though, it turned out to break other things – but in the end gave us some very valuable information.

First, a little background information.  XenDesktop uses an agent on the virtual workstation images that communicates with a server piece called the Desktop Delivery Controller (“DDC”).  This agent/server communication happens on TCP port 8080.

Unfortunately, in this specific case, the Citrix License Service was running on the same server as the DDC service. And in the latest version of the license server service, Citrix changed the port that the License Management Console uses to communicate with the license server to…yeah, you guessed it: 8080.

This conflict prevented the XenDesktop machines from checking into the DDC, so the DDC, which, as you might infer from its name, is the broker service that controls the delivery of virtual desktops to client devices that request them, viewed them all as “offline”.  It therefore believed that there were no virtual desktops available, so no connection requests were being serviced. In technical terms, this is what we call a “bad thing.”

The solution in this case was to change the port that the License server and License Management Console communicate on to port 8082 – which just happens to be the port it used in previous versions… hmm…

It should be noted that this can affect more than just XenDesktop Agents.  Port 8080 is heavily used for other Citrix functions, such as the XML service.  Why Citrix would change the license service to port 8080? Why do people jump out of perfectly good airplanes? Guess it seemed like a good idea at the time…to somebody, anyway.

Once we started digging for it, we found detailed steps on editing the license server configuration in the License Server 11.6 readme, and it’s obvious from the text that Citrix knew using port 8080 could cause conflicts:

When you install the license server components, version 11.6.1, on the same server as other Citrix products, the License Management Console is configured to use port 8080, by default, which may conflict with the other Citrix products (for example, they may use the Citrix XML Service which may use 8080 as well). To resolve this issue:

1. Navigate to C:Program FilesCitrixLicensingLMCtomcat
   confserver.xml
2. Open the file in Wordpad.
3. Replace the port number (8080) in the following line with 8082:
   <Connector port=”8080″ protocol=”HTTP/1.1″
   connectionTimeout=”20000″ redirectPort=”8443″/>
4. Save the file.
5. Reboot the server.

The other way we could have solved the problem, of course, would have been to move the license service to a server that had no other Citrix components running on it. We generally recommend that as a best practice, if at all possible (although we realize that sometimes it isn’t).  It just makes things easier in the long run.