Summary Citrix Metaframe XP

Citrix Metaframe is an add-on that can be used on Windows 2000 terminal services. It has the following extra abilities :

Why Citrix Metaframe ?

ICA instead of RDP

Citrix uses the Independent Computer Architecture protocol instead of Microsoft' Remote Desktop Protocol. Differences are :

Versions and licensing

There are three versions of Citrix XP available :

When you buy Citrix XP for the first time it offers a product license and 20 connection licenses. You can install Citrix XP on multiple servers within the same farm with one product license. Only additional connection licenses must be bought when there are more than 20 concurrent connections required. A new Citrix product license is not required for an editional server. 

The Citrix Management Console should be used to add licenses and to activate the license and machine code at Citrix. (within 35 days) 

The Citrix management console and Qfarm- and Qserver tool give an overview of the licenses installed and in use.

ICA client

Installation

The ICA client can be installed in various ways :

Customize the client and connections

The appsrv.ini and pn.ini files can be used to customize the ica connections and applications sets, to lock down the client, to maintain the ica settings and to give disaster recovery information. These files should be modified in the folder from which the client is installed. After the installation the files are stored in the \application data\ica client folder of the users' profile. 

PN.ini

The pn.ini file contains the information of the application set connections and published applications.

Appsrv.ini

The appsrv.ini file contains the information of the custom ica connections and the general ica settings.

For more information about the ini-files see ini file reference.pdf

Example of items that can be customized are :

Program neighborhood

The program neighborhood contains the connections to custom ica desktops or applications and published application sets. A published application set offers the user a set of applications that is published to him. This set of applications is refreshed every time the program neighborhood is started. This offers a very flexible solution.

Client update

By using the Citrix Client Update feature you can update the ICA clients automatically to the latest version when they connect to a server :

ICA connection center

After the installation of the ICA client, the ICA connection center is available in the taskbar. The utility has the following abilities :

Installing Citrix

Citrix management console

The Citrix management console is a Jav-based modular console to manage the Citrix environment within the enterprise. It is recommended to use it as a published application (\citrix\administration\ctxload.exe) but it can also be installed autoroot.exe file on the Citrix cd. The console has the following functions :

Application publishing

After the applications are installed they can be published by using the Application folder\Publish application option within the Citrix management console. Now you can customize the following settings per published application :

Load management

When an application is published on more than one server, it is load balanced. The users will be spread over the servers by the load evaluators. These load evaluators exists of a set of customized load evaluation rules. Each server has such an evalution rule which is by default based on the number of connected users. A load evaluator can be assigned to a server or to specific applications running on a server. The highest value of both determines the load value.
The following load evaluator rules are available :

The load is calculated within a scale of 0 to 10000 :

Special values are :

When a client connects to a load balanced application the following actions happen :

1. Client connects to the server as specified in the properties of the application.
2. The server passes the request to the data collector if it is not the data collector.
3. The data collector looks to see which servers offer the application.
4. The load values of all servers are determined. If a server and the application on the server both have load evaluators, the highest value counts as the value for the server.
5. The data collector sends the client to the server with the lowest load.
6. The client connects to that server.
7. This server sends an update about the load to the data collecter.

A load evaluator can be assigned to a server via the Load Manage Server option available for each server in the Servers folders.
You  can assign load evaluators to applications by using the Load Manage Application option in the Applications folders.

New load evaluators can be created by using the New Load Evaluator option under the farm name.

Load monitoring can be done via the Load Manager Monitor available under the Servers folder. It can also be done with the Query Farm /App command.

Citrix connection configuration tool

This console is used to manage the connections to the Citrix server. By default it contains the ICA connections for all available protocols and a RDP connection over TCP. Most of these settings can also be set at user or client level. When they are set on multiple levels, the settings on the server overrule the settings on the user or client level. Within Windows .NET server 2003, it is also possible to manage these settings via the group policies.

For each connection you can modify the following tabs :

Edit connection screen

Advanced tab

Client settings

ICA settings (not available on RDP protocol)

The Citrix Connection Configuration can also be used to create an async connection via a modem(-pool) :

Idependent Management Architecture (IMA)

The independent management architecture is the architecture of Citrix Metaframe. It has its own service and protocol that is running on each Citrix Metaframe server. The architecture has the following items :

Server farm

A set of Citrix servers can be part of a farm. A farm is established when the first Citrix Metaframe server is installed. A new farm should only be established if there a specific administration need. A new farm also requires a new 'start' license.

Data store

Each form has a central data store. This store can be a MS Access, SQL or Oracle database. This store contains the following information :

Each server in the farm can access and modify this information. This can be done in two ways :

To have this information available when the data store not available, each server has its own Local Host Cache. This cache contains a subset of the information available in the data store and is stored in the MS Access imalhc.mdb file. With this information, the server can run 48 hours without the data store. When information changes in the data store it is replicated to the local host caches.
The data store can be maintained with the dsmaint utility.

Data collector

The data collector maintains all Citrix farm related information like :

Each zone elects one server as the data collector which communicates with the server that contains the data store. This data store contains all the information and can be a MS Access, MS SQL server or Oracle database.

Zones

Servers in different areas can be put into different zones. (max. of 256 servers per zone) When the first server is installed, the first zone named by the subnet of the server, is created. An additional server can add an existing zone or create a new zone. Zones are created to reduce network traffic between different areas and to reduce processor usage caused by large information available about the other servers.

Zone data collector

Each zone has a zone data collector that collects and shares information with the server with its zone. It also exchanges information with the zone data collectors of the other zones in the farm. Information that is shared :

When using an MS Access database as data store, this server becomes automatically the zone data collector for that zone. It is recommended to run the data store and zone data collector on the same server when using a MS Access database as data store. When possible use a dedicated server as data store and zone data collector. Citrix uses the following procedure to select a zone data collector :

1. Highest master version number of the IMA service.
2. Lowest master ranking number of the server. The first server in a farm gets number 1, additional servers get number 3. You can change this number in the registry. 
3. Highest host ID. This ID is created randomly when the server is installed.

An election for a zone data collector is started when :

The Qfarm utility can be used to see which server is the zone data collector.

Security issues

Anonymous access

Within Citrix you can publish a desktop or application and allow anonymous login. For these logons the automatically created account Anon000 to Anon014 are used. These accounts are member of the Guests group and the Anonymous group that was created by Citrix.

SpeedScreen

SpeedScreen arranges that only that part of the screen is refreshed that is changed. This decreases the required bandwidth. It also offers SpeedScreen Latency Reduction which exists of two parts :

Internet access

Citrix uses to different ports. The first port-set is for the ICA traffic that contains the screen updates, mouse movement, printer-data, sound etc. (traffic port) The second port-set is to browse for ICA services like applications, servers, etc.  (browsing port) The following traffic ports are used :

These are the browsing ports :

Other management-related ports are :

SSL

With Citrix Metaframe FR1 and clients with version 6.20 or later, you can encrypt all ICA traffic with SSL. All traffic uses than port 443. This requires the following actions :

NAT

When Network Address Translation (NAT) is used to access the servers changes on the server and client side have to be made. On the server side, the altaddr command must be used to connect the external ip addresses to the Citrix Metaframe servers. In the Citrix Program Neighborhood you have to use he Firewall button and the 'Use alternate address for firewall connection'-option when you add an application set.

Command line tools

Links

Last update : 15 February 2003