After upgrade of the device from 1.3.x to 2.1 (or initial install of CA 2.1) the network interfaces are disabled by default. This is due to the design of the underlying subsystem (COE).
Due to COE 3, if there are interfaces that have not been configured, the settings will not be migrated on upgrade. In addition, COE 3 has interfaces disabled by default, which will restrict the interfaces from appearing in the UI configuration.
You will be required to access the CLI and enable the interfaces desired for configuration.
Example:
CAS> en
CAS# config
Enter configuration commands, one per line. End with CTRL+Z.
CAS(config)# interface 1:0 enable
After completing the above process for each interface desired, the interface will be available to configure within the UI, as well as the static On-Box Sandbox dirty line setting.