LAN-to-WAN Configuration and Change Management

The LAN-to-WAN Domain exists to provide a structured transition between your LAN and a WAN, such as the Internet. Much of the functionality in the LAN-to-WAN Domain depends on the configuration of the devices in the domain. Each device or software component operates based on configuration settings and rules. Any change to settings or rules changes the way the domain components operate.

After you configure the components in the LAN-to-WAN Domain to operate securely, it is important to prohibit unauthorized changes to the domain configuration. Any configuration changes you make will change the way components operate. Changes can be beneficial or detrimental. You must enforce a change-management process to ensure you only make authorized changes to any configuration and that you document all changes for later auditing.

The change-management process is fairly simple and contains only a few steps. Each step is important and contributes to the overall security of your environment. Here are the basic configuration-management steps required to make any changes to device configuration settings or rules:

1. The requestor submits a configuration setting or rule change request. It is important to document each change and the reason for the change. Auditing configuration changes and comparing the impact of similar changes requires as much historical information as possible.

2. The configuration control board (CCB) reviews each request and either approves or denies it. The CCB can be a group of people or a single person with the responsibility to evaluate changes.

3. The implementers—generally security administrators—receive approved change requests for implementation and make the approved changes.

4. Before making any changes, security administrators should validate the current configuration against the latest authorized baseline. This step identifies any unauthorized changes.

5. Security administrators should validate any configuration changes in a test environment whenever possible.

6. After applying authorized changes, security administrators should create a new authorized baseline.

7. The implementers should validate the changes made to ensure they satisfy the original request.

Although it might seem like an intrusive process, requiring all configuration changes to go through a change-management procedure allows you to audit all authorized changes and deploy only approved changes. The overall configuration-management process should also include periodic audits of each component’s configuration against the latest baseline to identify unauthorized changes. In this way, you can ensure your LAN-to-WAN components maintain a secure configuration.