Product Documentation

Sample Deployment with the Secure Gateway (Double Hop)

Oct 09, 2015

This deployment uses Secure Gateway in a double-hop configuration to provide TLS/SSL encryption between a secure Internet gateway server and an SSL-enabled plugin, combined with encryption of the HTTP communication between Secure Gateway and the Web browser, the Web Interface, and the Secure Gateway proxy. Additionally, you can secure ICA traffic within the internal network using IPSec.

This diagram shows sample deployment C, which uses Secure Gateway in a double-hop configuration.


The following table lists the components of the deployment and the operating systems required for the servers and client devices.

  Components Operating systems

XenApp farm

XenApp 6.0 for Microsoft Windows Server 2008 R2

SSL Relay enabled

Secure Ticket Authority installed on XenApp server

Windows Server 2008 R2

Web server

Web Interface 5.3 for Internet Information Services

Windows Server 2008 R2

Windows Server 2008

Windows Server 2003 with Service Pack 2

.NET Framework 3.5 or 2.0 (IIS 6.0 only)

Visual J#.NET 2.0 Second Edition

Secure Gateway Service

Secure Gateway Proxy

Secure Gateway 3.2 for Windows

Windows Server 2008 R2

Windows Server 2008

Windows Server 2003 with Service Pack 2

User devices

Citrix online plug-in for Windows 12.x

TLS-enabled Web browser

Windows 7

Windows Vista

Windows XP Professional

How the Components in Interact

Here, the DMZ is divided into two sections by an additional firewall. The server running the Secure Gateway Service is located in the first section of the DMZ. The Web Interface and the Secure Gateway Proxy are located in the second section. Users connect to the Secure Gateway Service located in the first section of the DMZ.

Use TLS to secure the connections between client devices and Secure Gateway. To do this, deploy TLS/SSL-enabled plug-ins and configure Secure Gateway at the network perimeter, typically in a DMZ.

This diagram shows a detailed view of sample deployment C.


In this deployment, Secure Gateway removes the need to publish the address of every XenApp server in the farm and provides a single point of encryption and access to the farm. Secure Gateway does this by providing a gateway that is separate from the XenApp servers and reduces the issues for firewall traversal to a widely accepted port for ICA traffic in and out of the firewalls.

To comply with FIPS 140, secure the communication between the Secure Gateway Proxy and the server farm using IPSec.

Security Considerations for This Deployment

IPSec in Sample Deployment C

To enable IPSec to secure communication between the Secure Gateway Proxy and the XenApp server farm, you must configure IPSec on each server, including the Secure Gateway Proxy.

IPSec is configured using the local security settings (IP security policies) for each server. In sample deployment C, IPSec is enabled on the requisite servers and the security method is configured for 3DES encryption and SHA-1 integrity to meet FIPS 140 requirements.

FIPS 140 Validation in Sample Deployment C

In this deployment, the SSL Relay uses the Microsoft cryptographic service providers and associated cryptographic algorithms available in the Microsoft Windows CryptoAPI to encrypt and decrypt communication between client devices and servers. For more information about the FIPS 140 validation of the CSPs, see the Microsoft documentation.

For Windows Vista, Windows XP, Windows Server 2008, and Windows Server 2003, TLS/SSL support and the supported ciphersuites can also be controlled using the following Microsoft security option:

System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing

For more information, see the documentation for your operating system.

TLS/SSL Support in Sample Deployment C

You can configure Secure Gateway and the Web Interface to use either the Transport Layer Security 1.0 protocol or the Secure Sockets Layer 3.0 protocol. In sample deployment C, the components are configured for TLS.

Supported Ciphersuites for Sample Deployment C

In this deployment, Secure Gateway, the Secure Gateway Proxy, and the Web Interface can be configured to use government-approved cryptography, such as the ciphersuite RSA_WITH_3DES_EDE_CBC_SHA, to protect “sensitive but unclassified” data.

Alternatively, for TLS connections, you can use AES as defined in FIPS 197. The government ciphersuites are RSA_WITH_AES_128_CBC_SHA for 128-bit keys and RSA_WITH_AES_256_CBC_SHA for 256-bit keys. As defined in Internet RFC 3268 http://www.ietf.org/rfc/rfc3268.txt, these ciphersuites use RSA key exchange and AES encryption. For more information about AES, see http://csrc.nist.gov.

Certificates and Certificate Authorities in Sample Deployment C

Citrix products use standard Public Key Infrastructure (PKI) as a framework and trust infrastructure. In sample deployment C, one server certificate is configured on Secure Gateway, one on the Secure Gateway Proxy, and one on the Web Interface. A certificate is also configured on each XenApp server.

Smart Card Support in Sample Deployment C

Smart card authentication is not supported in sample deployment C. You cannot configure smart card support when Secure Gateway is positioned between the client devices and the Web Interface to provide a single point of access to the server farm.

Plug-ins Used in Sample Deployment C

In this deployment, users access their applications using the Citrix plug-in. For more information about the security features and capabilities of Citrix plug-ins, see Receiver and Plug-in Security.