Deploy Citrix Gateway in a double-hop DMZ

Some organizations use three firewalls to protect their internal networks. The three firewalls divide the DMZ into two stages to provide an extra layer of security for the internal network. This network configuration is called a double-hop DMZ.

Figure 1. Citrix Gateway appliances deployed in a double-hop DMZ

Note:

For illustration purposes, the preceding example describes a double-hop configuration using three firewalls with StoreFront, the Web Interface, and Citrix Virtual Apps, but you can also have a double-hop DMZ with one appliance in the DMZ and one appliance in the secure network. If you configure a double-hop configuration with one appliance in the DMZ and one in the secure network, you can ignore the instructions for opening ports on the third firewall.

You can configure a double-hop DMZ to support Citrix StoreFront or the Web Interface installed parallel to the Citrix Gateway proxy. Users connect by using Citrix Workspace app.

Note:

If you deploy Citrix Gateway in a double-hop DMZ with StoreFront, email-based AutoDiscovery for Citrix Workspace app does not work.

How a double-Hop deployment works

You can deploy Citrix Gateway appliances in a double-hop DMZ to control access to servers running Citrix Virtual Apps. The connections in a double-hop deployment occur as follows:

• Users connect to Citrix Gateway in the first DMZ by using a web browser and by using the Citrix Workspace app to select a published application.

• Citrix Workspace app starts on the user device. The user connects to Citrix Gateway to access the published application running in the server farm in the secure network.

  Note: Secure Hub and the Citrix Gateway plug-in are not supported in a double-hop DMZ deployment. Only the Citrix Workspace app is used for user connections.

• Citrix Gateway in the first DMZ handles user connections and performs the security functions of an SSL VPN. This Citrix Gateway encrypts user connections, determines how the users are authenticated, and controls access to the servers in the internal network.
• Citrix Gateway in the second DMZ serves as a Citrix Gateway proxy device. This Citrix Gateway enables the ICA traffic to traverse the second DMZ to complete user connections to the server farm. Communications between Citrix Gateway in the first DMZ and the Secure Ticket Authority (STA) in the internal network are also proxied through Citrix Gateway in the second DMZ.

Citrix Gateway supports IPv4 and IPv6 connections. You can use the configuration utility to configure the IPv6 address.

The following table suggests the double-hop deployment support for the various ICA features:

Prepare for a double-hop DMZ deployment

To prepare appropriately and avoid unnecessary problems when configuring a double-hop DMZ deployment, you must answer the following questions:

• Do I want to support load balancing?
• What ports do I must open on the firewalls?
• How many SSL certificates do I need?
• What components do I need before I begin the deployment?

The topics in this section contain information to help you answer these questions as appropriate for your environment.

Components required to begin the deployment

Before you begin a double-hop DMZ deployment, ensure that you have the following components:

• At minimum, two Citrix Gateway appliances must be available (one for each DMZ).

• Servers running Citrix Virtual Apps must be installed and operational in the internal network.

• The Web Interface or StoreFront must be installed in the second DMZ and configured to operate with the server farm in the internal network.

• At minimum, one SSL server certificate must be installed on Citrix Gateway in the first DMZ. This certificate ensures that the Web browser and user connections to Citrix Gateway are encrypted.

  You need extra certificates if you want to encrypt connections that occur among the other components in a double-hop DMZ deployment.