- Understanding the Need for ISA Server 2006
- Detailing the Additional Advantages of ISA Server
- Understanding the History of ISA Server 2006
- Exploring ISA Server 2006's New Features
- Detailing Deployment Strategies with ISA Server 2006
- Augmenting an Existing Security Environment with ISA Server 2006
- Administering and Maintaining an ISA Server 2006 Environment
- Using ISA Server 2006 to Secure Applications
- Best Practices
Exploring ISA Server 2006's New Features
In addition to the enhanced features in ISA Server 2000, ISA Server 2004 and 2006 introduced the following new features:
- Multiple network support and per-network policies—ISA Server 2006 introduced the capability to set up and secure ISA between multiple networks. For example, you can set up ISA to act as a firewall between the Internet, an internal network, a perimeter (DMZ) network, a wireless access network, a VPN clients network, and many more. In addition, you can configure unique policies between each network, such as restricting traffic to a DMZ network or securing RPC traffic across WAN segments. For more information on this feature set, see Chapter 5, "Deploying ISA Server 2006 as a Firewall."
- Support for complex and customizable protocols—In addition to including a wide array of known protocol support for rules, ISA Server 2006 includes support for custom protocols. These protocols can be defined and specific filters can be created to scan for defined attack patterns in the custom traffic.
- New server and OWA publishing rules—ISA Server 2006 includes a vast assortment of server publishing rules, including sophisticated OWA publishing rules that utilize advanced functionality such as forms-based authentication and reverse-proxy capabilities. For additional reading on these features, see Chapter 12, "Securing Outlook Web Access (OWA) Traffic."
- Remote Procedure Call (RPC) filtering support—Of particular note in ISA Server 2006 was the addition of RPC filtering support, which enables an administrator to specify what type of RPC traffic will be allowed from one network to another. For example, a rule could be set up to allow only MAPI Exchange access or Active Directory replication traffic across segments, while blocking other RPC access, such as the kind that spawns attacks and exploits. For more information on RPC filtering, see Chapter 14, "Securing Web (HTTP) Traffic."
- End-to-end secure web publishing capabilities—The web publishing rules improved in ISA Server 2006 allow for end-to-end securing of Secure Sockets Layer (SSL) encrypted web traffic from client to ISA Server, and then back to web server. When the traffic is decrypted at the ISA Server, it can be inspected for viruses and HTTP exploits. The traffic is then re-encrypted before being sent to the web server.
- RADIUS and SecurID authentication support—In addition to supporting Active Directory authentication, ISA Server 2006 now supports authentication natively against a RADIUS or RSA SecurID authentication infrastructure. This enables an ISA Server to be a member of a workgroup, as opposed to a domain member.
- Stateful inspection for VPN connections—In this version of ISA Server, all traffic that passes through ISA is inspected for Application-layer attacks (stateful inspection). This includes VPN connections as well.
- VPN quarantine control features—ISA Server 2006 introduces the capability to provide granular control to VPN clients by enabling administrators to restrict new VPN connections to a separate quarantine network. This network can have strict access restrictions placed on it. In this model, VPN users are not moved into the regular VPN users network until it can be established that they satisfy certain criteria, such as the installation of virus-scanning software.
- Enhanced monitoring, logging, and reporting—ISA Server 2006 includes superb reporting, monitoring, and logging capabilities, including capabilities to write logs to a SQL-desktop version (MSDE) database. ISA can be configured to automatically generate rich reports for client web access, security events, protocol utilization, and much more. Monitoring of ISA is further enhanced with the use of the ISA Management Pack for Microsoft Operations Manager (MOM) 2000/2005. For more information on monitoring ISA Server, refer to Chapter 19, "Monitoring and Troubleshooting an ISA Server 2006 Environment."
- Forms-based authentication for all web sites—This includes cookie-based auth forms for SharePoint Products and Technologies, OWA, and other web sites. This is a new feature in the 2006 release of the product.
- Enhanced branch office support tools—Another feature new in ISA 2006, the support for branch office VPN using ISA Server has been greatly enhanced and streamlined with a new Branch Office VPN wizard.
The wide variety of features included in ISA Server 2006 makes it very versatile, and it can be deployed to take advantage of one, two, or multiple functions. For example, ISA could be deployed as a full-function firewall, allowing VPN access and web caching. Or it could be deployed simply to filter RPC connections between network segments. An added advantage to this flexibility is the fact that only those functions that are required are turned on. This reduces the surface area that is exposed to attack, reducing the overall threat.
Choosing the Operating System for ISA Server 2006
It is necessary to install and deploy ISA Server 2006 servers on the Windows Server 2003 platform. Improvements in reliability, functionality, and, most importantly, security dictate this. With ISA Server 2004, it was previously possible, though not recommended, to install ISA Server 2004 on the Windows 2000 Operating System. This is no longer an option with the 2006 version. In fact, 2006 requires both 2003 and Service Pack 1 at a minimum to be installed.
It is important to note that because the ISA server holds a very important security role, it is essential that you patch the operating system with the critical updates Microsoft releases. This includes the necessary Service Pack 1 or Windows Server 2003 R2 Edition and any new Service Packs for ISA Server 2006, when they become available, which both introduce advanced security and functionality. For more information on updating ISA Server and Windows with the latest in security and updates, see Chapter 2, "Installing ISA Server 2006."
Choosing Between ISA Server 2006 Enterprise or Standard Editions
ISA Server 2006 comes in two versions: an Enterprise version and a Standard version. Each version offers different functionality, with the Standard version of the product geared toward small and mid-sized organizations, and the Enterprise version designed for medium to large organizations. The Enterprise version of the software includes all the functionality of the Standard edition, but with the addition of the following:
- Array Capabilities—ISA Server 2006 Enterprise edition includes the capability to create arrays, which allow multiple servers connected to the same networks to act in tandem to process firewall, VPN, and cache requests. These arrays use the Cache Array Routing Protocol (CARP) to communicate changes and topology information.
- Integrated Network Load Balancing (NLB)—In addition to the general NLB support provided by the Standard version, the Enterprise version of ISA Server includes advanced integrated support for NLB, allowing an administrator to make changes and manage NLB directly from the ISA Management Console.
- ADAM Centralized Storage—A huge improvement over ISA Server 2000 Enterprise edition is the added capability for Enterprise Configuration information to be stored in a separate instance of Active Directory in Application Mode (ADAM), rather than in the internal Active Directory forest schema. This enables the external-facing ISA Enterprise servers to maintain their configuration in an isolated environment, without unnecessarily exposing internal Active Directory services to attack.
- Centralized Management and Monitoring—ISA Server Enterprise edition allows for management of a highly scalable ISA solution, with multiple ISA arrays in multiple locations. This allows for centralized management of a complex network infrastructure.
For more information on the advanced capabilities of the Enterprise edition of ISA Server 2006, refer to Chapter 6, "Deploying ISA Server Arrays with ISA Server 2006 Enterprise Edition."