Understanding and configuring the Citrix XML Service

Understanding and configuring the Citrix XML Service’, ‘Recently caught out by modifying the Citrix XML Service port I thought I would share my experiences!

Citrix XML Service Port / ctxxmlss

The Citrix XML Service Port is used by the ICA Client for connection to the Citrix server / published application:When TCP/IP + HTTP is selected and you specify servers in the Address List box, the client communicates with the Citrix XML Service on a specified server for Enumeration.If you modify the XML service port from port 80 and rely on your clients to connect via HTTP & TCP/IP using the dns host entry for ‘ica’ for round-robin DNS resiliency you will find that this round-robin DNS for this entry will fail. This is because you cannot specify the port number, which the XML service is running on in DNS.Therefore, if the first Citrix server in your farm becomes unresponsive or is taken offline connections to the farm will failAs a result you need to configure your clients to use the default server address if ica:pn where pn is the port number you are using for the XML Service. For example’; ica:8080:

 This can be manually specified in an unattended install of the ica client. Run msiexec /a ica32pkg.msi and create an extracted network install source. Then once created edit the \\yourserver\yourshare\ Program Files\Citrix\Application\ICA Client\appsrv.ini file and add the following line at the end of the file:


This will also affect Thin Client devices that utilise HTTP & TCP/IP. For example WYSE 1200LE and S10 Thin Client devices. The solution for these devices is to edit the wnos.ini file on you FTP server so that the port number is specified:


You’ll find that without this if the first server in the list goes offline the TC devices will NOT connect to the next server in the list.


Changing the XML Service Port

You have two options when configuring the XML Service port; one, run the XML Service alongside IIS; two, run it on a dedicated port.To configure the XML service to run alongside IIS on port 80 see the following guide:


To configure the XML service to use a dedicated port:

First un-register the XML Service on the server you wish to modify the port:ctxxmlss /u

Now re-register the service on your desired port number:ctxxmlss /r8080