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Exploring the ISA General Node

Any of the settings that were not explicitly defined in the other nodes of the ISA console were placed together in the General node. The General node, shown in Figure 3.36, contains several links to key functionality that are not found anywhere else, and is therefore important to explore.

Figure 3.36

FIGURE 3.36 Exploring the General node in the ISA Console.

Delegating ISA Administration

The first link listed under the ISA General node is the Administration Delegation link. This link makes it possible to enable other administrators within an organization to monitor and/or administer the ISA Server Console. The delegation process is streamlined through the use of a wizard, which leads administrators through the entire process.

To allow an individual or a group of users to administer the ISA Server system, perform the following steps:

  1. Open the ISA Server Management Console (Start, All Programs, Microsoft ISA Server, ISA Server Management).
  2. From the console tree, select the General tab by clicking on it.
  3. In the Central Details pane, click the Administration Delegation link.
  4. When the wizard starts, click Next to continue.
  5. In the Delegate Control dialog box, click the Add button to add a group or user.
  6. In the Administration Delegation dialog box, enter the name of the group or user that will be added, similar to the example shown in Figure 3.37.

    Users or groups can be local accounts, or they can be domain accounts if the ISA Server is joined to an Active Directory domain.

    Under the Role field in this dialog box, three types of administrators are available to choose from, each with its own varying level of permissions and abilities. The three types are

    • ISA Server Basic Monitoring  This type of administrator can view the ISA monitoring console and items such as the Dashboard but cannot configure any of the settings.
    • ISA Server Extended Monitoring  An ISA Extended Monitoring Admin can monitor ISA and is also capable of customizing monitoring components. All other ISA configuration components are listed as read-only to this type of Admin.
    • ISA Server Full Administrator  A Full Administrator can configure and change any ISA Server components.
    Figure 3.37

    FIGURE 3.37 Delegating ISA administration.

Then do the following:

  1. Choose the role of the administrator to be added using the criteria already outlined. Click OK when finished.
  2. Click the Add button and repeat the procedure for any additional groups or users that will be added.
  3. After returning to the Delegate Control dialog box, as shown in Figure 3.38, review the addition(s) and click Next to continue.

    Figure 3.38

    FIGURE 3.38 Specifying groups to be added as ISA Administrators.

  4. Click Finish on the completion screen.
  5. Click the Apply button at the top of the Central Details pane.
  6. Click OK at the confirmation dialog box.

Configuring Firewall Chaining

Firewall chaining is an additional option that can be configured via the General node. With Firewall chaining, multiple ISA servers can be configured to forward client requests to upstream ISA servers. This enables them to be routed to "parent" ISA servers, for the purposes of directing the flow of traffic from one network to another.

Firewall Chaining settings can be set up by clicking the Configure Firewall Chaining link in the Central Details pane.

Defining Firewall Client Parameters

The full-featured firewall client, available as an option for ISA implementations, allows for customized user-based policies and application-specific filtering using Winsock-compatible applications. Specific firewall client settings are available in the General node of the ISA Server Console by clicking on the Define Firewall Client Settings link. These settings allow for options such as whether or not downlevel (ISA 2000) client connections will be allowed and what type of Winsock applications to support through the firewall client, as shown in Figure 3.39.

Figure 3.39

FIGURE 3.39 Defining firewall client settings.

For additional information on using the firewall client, see Chapter 11.

Exploring Link Translation

Link translation, an option fully explained in Chapter 14, is a process by which a web server published through ISA Server automatically translates embedded links in the page into a different format. This can be useful when a web server, such as an intranet server, provides links to internal server names that are not resolvable on the Internet. Through the process of link translation, these internal names, such as http://server20 can be translated into a publicly accessible link names, such as https://sharepoint.companyabc.com, for example.

The General node makes it possible to configure what type of content is parsed for link translation via the Configure Link Translation link. This link invokes the dialog box shown in Figure 3.40, which enables administrators to choose additional content types to be parsed for link translations.

Figure 3.40

FIGURE 3.40 Configuring Link Translation options.

When these options are selected, individual web publishing rules that are configured with link translation can then apply those link translation options to the additional content types chosen from this list.

Configuring Dial-Up Preferences

The Specify Dial-Up Preferences link in the Central Details pane allows ISA Server to be configured to utilize dial-up networking to establish links to specific networks. The options available in this link allow for specific dial-up account information, dial-up preferences, and dial-up connection information to be entered and configured for ISA servers that require this type of capability.

Examining Certificate Revocation Options

The Specify Certificate Revocation link makes it possible to have the ISA Server check incoming client certificates to make sure that they are not in the Certificate Revocation List (CRL). The dialog box shown in Figure 3.41 illustrates the default options for certificate revocation in an ISA Server.

Figure 3.41

FIGURE 3.41 Configuring certificate revocation options.

Although ISA can easily check incoming client certificates, the ISA Server can check only to see whether a server certificate has been revoked if it initiates the Secure Sockets Layer (SSL) connection itself, normally performed when the server is configured as a web proxy for the clients. This option can further secure web browsing for clients by making sure that server certificates on the Internet are valid.

Viewing ISA Server Details

ISA Server details, such as the specific version used, the product ID, the installation directory, and the creation date of the server are accessible via the View ISA Server Computer Details link in the Central Details pane. These details are mainly useful for determining the current version of ISA Server that is running on the server.

Defining Connection Limits

By default, individual clients that access an ISA server are limited to a specific number of connections per second, per rule. This helps to stem the effects of Denial of Service (DoS) attacks that target servers by overloading them with requests. In certain cases, exceptions may need to be made if individual servers need to establish a large number of connections, such as in the case of an SMTP or DNS server. These settings can be configured in the Connection Limits dialog box, shown in Figure 3.42.

Figure 3.42

FIGURE 3.42 Setting exceptions to connection limits.

This dialog box is invoked by clicking on the Define Connection Limits link in the Central Details pane. Determining whether exceptions need to be made can be accomplished by checking the alerts in the Monitoring node and looking for specific alerts that indicate that a session was terminated because of connection limit settings.

Setting Intrusion Detection Thresholds

Intrusion detection settings, covered in detail in Chapter 19, can be configured by clicking the Enable Intrusion Detection and DNS Attack Detection link in the Central Details pane. These options, shown in Figure 3.43, allow for the customization of what types of attacks will be reported as alerts in the ISA Console.

Figure 3.43

FIGURE 3.43 Enabling intrusion detection filters.

It is recommended to enable all the intrusion detection filters and to closely watch for these type of attacks. An increase in intrusion detection attempts can signal a full-blown attack against the ISA Server.

Defining RADIUS Servers

Remote Dial-In User Service (RADIUS) Servers can be configured by clicking the Define RADIUS Servers link in the General node of the Console. RADIUS servers are typically utilized for authentication when the ISA Server is not a member of an Active Directory domain and/or when the server is configured as an appliance reverse proxy server in the DMZ of an existing firewall. For more information on this concept, reference Chapter 7, "Deploying ISA Server as a Reverse Proxy into an Existing Firewall DMZ."

Defining IP Preferences

The IP Preference settings, invoked via the Define IP Preferences link, allow for advanced IP options filtering to be configured, as shown in Figure 3.44. This allows for IP characteristics such as time stamp, router alert, strict source route, and others to be blocked or allowed.

Figure 3.44

FIGURE 3.44 Setting IP preferences.

In addition to filtering based on IP options, this dialog box also allows for IP routing to be enabled, which allows for original packets received by the ISA server to be forwarded to their destinations. If this option is not enabled, ISA repackages the data in its own packet and forwards it to the destination server—a more secure option, but one that requires additional overhead on the server. For more information on these options, see Chapter 15.

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