The Perimeter Defense guns were built in between Season One and Season Two, and consisted of 4 to 6 light turrets.
Purpose[]
The purpose of the Perimeter Defense Guns were to protect the survivors against any external threat. When The Drones finally start to attack, within a week the Wall is heavily damaged but some defense guns remained online. Until the Type 6 attacked anyway.
Status[]
CaptainShack says he was surprised the wall held out as long as it did. The wall is mostly destroyed after the Type Six attack.
Other Walls and Defense Guns[]
Morph's binocular view of incomplete walls
There were other walls that were going to be built by the survivors, as seen in Dr Morphologis binocular view in Intelligence. They were built next to the already existing guns. Along Commander W4stedspace's already existing defenses some additional guns were created. The Guns were completed but they were quickly destroyed by enemy Drones.