11-12 User’s Reference GuideAn approach to using filtersThe ultimate goal of network security is to prevent unauthorized access to the network without compromisingauthorized access. Using filter sets is part of reaching that goal.Each filter set you design will be based on one of the following approaches:■ That which is not expressly prohibited is permitted.■ That which is not expressly permitted is prohibited.It is strongly recommended that you take the latter, and safer, approach to all of your filter set designs.Working with IP filters and filter setsThis section covers IP filters and filter sets..To work with filters and filter sets, begin by accessing the filter set screens.Note: Make sure you understand how filters work before attempting to use them. Read the section “Aboutfilters and filter sets,” beginning on page 11-4.The procedure for creating and maintaining filter sets is as follows:1. Add a new filter set.2. Create the filters for the new filter set.3. View, change, or delete individual filters and filter sets.The sections below explain how to execute these steps.Adding a filter setYou can create up to eight different custom filter sets. Each filter set can contain up to 16 output filters and upto 16 input filters.MainMenuSystemConfigurationFilterSetsFilter SetsAdd Filter Set...Display/Change Filter Set...Delete Filter Set...
