Defend Port from attack is a mission in Jak 3. Torn had gotten word of a two-pronged assault from both the Metal Heads as well as the KG Death Bots. Due to the scale of the attack he put Jak on the frontlines.
The PlayStation 3 and Vita versions of this mission are related to a trophy named "Port to Starboard", completing this mission will reward you with a silver trophy.
A rather unique combat-only mission where you are moved automatically from spot to spot and have to fight in these sort-of mini-arena's with a high camera that looks down on the area and your surroundings. Enemies come in from all sides with only soldiers who will help out fighting the enemies. Near the end there are also civilians who will drop on the floor and lay flat, these are best ignored.
There is an annoying restriction in that you can't choose your own weapon. You are standardly equipped with the Blaster (With unlimited ammo, so begin using the aerial wastelander combo as much as possible) with others coming in randomly. It's recommended to just start using your new weapons as much as possible as you will get a new one soon enough, there is no need to conserve ammunition.