Citrix AltAddr – Often Overlooked?
Over the past year I have personally built and implemented around six Citrix XenApp / Presentation servers and assisted with a handful of others. Most of they guys I work with are pretty sharp and capable of handling almost any technology situation. However – I have been noticing more and more during Citrix implementations that a lot of people have been overlooking adding the alternate address for the XenApp server.
The altnernate address is added via running altaddr in the command line and provides the server with an external IP address alternate for servers residing behind firewalls. The alternate address must be set if you intend to have your server behind a firewall with a private IP address. So if you have placed your server behind a firewall (always a good idea) on your LAN you will have internal access but no external access until the alternate address is set and you have set the connection method to Alternate in the web interface settings.
The syntax is pretty straight forward for the command and is as follows (all from the command prompt):
- atladdr: Simply running altaddr will query the alternate address of your server.
- atladdr /set: Will allow you to set the alternate address. This must be followed by the public IP you wish to use for you server. Example: altaddr /set 172.16.0.15 (I know, this is a private IP but just replace this with your public IP).
- atladdr /delete: Will delete the alternate address.
- altaddr /server:servername: will allow you to specify the server name you wish to access.
The major difference here between a regular terminal server and a Citrix XenApp server is that you need to do more than just open a port on the firewall. For a terminal server you can simply open up the port you wish to connect on (default 3389) and map your public IP to your private IP. For Citrix XenApp you will need to open the firewall port for ICA connections (default 1494) as well as set your alternate address and your default connection method to alternate.