When you use Application Security Manager (ASM) to create a security policy attached to a virtual server, the BIG-IP system automatically creates a local traffic policy. The local traffic policy forms a logical link between the local traffic components and the application security policy.
By default, the system automatically creates a simple local traffic policy directs all HTTP traffic coming to the virtual server to the ASM security policy that you created. ASM examines the traffic to ensure that it meets the requirements of the security policy. If that is all you need to do, your task is done. If, however, you want more flexibiliy, such as applying different security policies depending on the type of traffic or disabling ASM for certain types of traffic, you can use the local traffic policy to do that.
Local traffic policies can include multiple rules. Each rule consists of a condition and one or more actions to be performed if the condition holds. So you can create a local traffic policy that works with ASM and includes multiple rules that do different things depending on the conditions you set up. In this type of traffic policy, each rule must include one of these ASM actions:
For example, you may want a local traffic traffic policy directed to a specific URL to enforce a security policy. As a default rule, all other traffic could disable ASM. You can also direct people using different aspects of an application (or different applications) to various security policies. Many other options are available for directing ASM traffic using local traffic policies.
If you use the Deployment wizard to create a security policy not attached to a virtual server, the system creates the security policy but does not create a local traffic policy. However, you will need to have a virtual server and local traffic policy to select the traffic for the security policy to enforce.
In that case, you can develop the security policy adding the features that you want to use. Without a virtual server, the system cannot build the security policy automatically until you have traffic going through. But you can manually develop the security policy.
When you are ready to enforce the security policy and start sending traffic through the system, create a virtual server with an http profile, and enable the security policy you created in the virtual server resources. When you save the virtual server, the system automatically creates a default local traffic policy that enforces the security policy on all traffic. You can edit the local traffic policy rules if you want more flexibility concerning how the security policies are implemented.
Application Security Manager applies security policy rules to traffic that is controlled and defined using a local traffic policy. To provide more flexibility in selecting the traffic, you can edit the local traffic policy and add rules to it.
This implementation shows how to create a security policy and edit at the local traffic policy that is created. The example provided describes how to add rules to the local traffic policy so that the security policy applies only to administrative traffic beginning with /admin. No security policy applies to the other traffic.
Many other options are available for configuring local traffic policies with ASM. By following through the steps in this example, you can see the other options that are available on the screens, and can adjust the example for your needs.
|Fundamental||Creates a security policy enforcing HTTP protocol compliance, evasion techniques, explicit file types (including length checks), explicit parameters in selective mode at the global level, attack signatures, the violation Request Length Exceeds Defined Buffer Size, host names, header lengths, cookie lengths, the violation Failed to Convert Character, and learn explicit redirection domains.|
|Enhanced||Creates a security policy with all the elements of the Fundamental policy type; also checks for explicit URLs in selective mode plus meta characters, Explicit parameter length checks in selective mode at the global level, methods, explicit cookies, and content profiles.|
|Comprehensive||Creates a security policy with all the elements of the Enhanced policy type; also checks for explicit URLs and meta characters, explicit parameters and lengths at the URL level, parameter meta characters, and dynamic parameters.|
|Fast||Use if your application supports a small number of requests from a small number of sessions; for example, useful for web sites with less traffic. However, choosing this option may present a greater chance of adding false entities to the security policy.|
|Medium||Use if your application supports a medium number of requests, or if you are not sure about the amount of traffic on the application web site. This is the default setting.|
|Slow||Use if your application supports a large number of requests from many sessions; for example, useful for web sites with lots of traffic. This option creates the most accurate security policy, but takes Policy Builder longer to collect the statistics.|
|All||Specifies that the policy trusts all IP addresses. For example, if the traffic is in a corporate lab or preproduction environment where all of the traffic is trusted, the policy is created faster when you select this option.|
|Address List||Specifies networks to consider safe. Fill in the IP Address and Netmask fields, then click Add. This option is typically used in a production environment where traffic could come from untrusted sources. The IP Address can be either an IPv4 or an IPv6 address.|
When you have completed the steps in this implementation, you have configured the Application Security Manager (ASM) to enforce security policy rules only on traffic with a URI beginning with /admin. All other traffic bypasses ASM.
This is simply one way to illustrate how you can use a local traffic policy to determine different conditions and specify multiple actions instead of having all traffic treated the same way. We encourage you to explore the local traffic policy options and documentation to learn how to use this flexible feature to best suit your needs.