For a heavy forwarder (HF), you should set up one of the following options:
1) Make the HF a slave of a license master. This will give the HF all of the enterprise capabilities - and the HF will consume no license, as long as it does not index data.
2) Install the forwarder license. This will give the HF many enterprise capabilities, but not all. The HF will be able to parse and forward data. However, it will not be permitted to index and it will not be able to act as a deployment server (as an example). This is the option I would usually choose. (Note that the Universal Forwarder has the forwarder license pre-installed.)
I strongly discourage using either the trial license or the free license on a production forwarder.
