Select a subset of test cases to be used for regression testing purposes during normal operations. These should include cases that verify that all incoming and outgoing packets are being routed, filtered, and logged as expected as well as service-specific cases that verify those packets requesting specific services (WWW, email, FTP, etc.) are being routed, filtered, and logged as expected.

Once the new firewall system is part of normal operations, you can use selected regression test cases to verify that a change does not affect operational capabilities that worked successfully prior to the change.