@Glennn,
While Israel maintains control over some aspects of Gaza's borders, particularly its airspace & maritime borders, Egypt controls the southern border.
Following Israel's unilateral withdrawal from the Gaza Strip in 2005, it implemented a blockade along with Egypt, restricting the movement of goods and people in and out of Gaza. This blockade has been a subject of controversy and criticism from humanitarian organizations, as it has significantly affected the living conditions of the Gazan population.
The purpose of the blockade is to protect Israel from attack.
Egypt's control over the southern border with Gaza, particularly the Rafah border crossing, has also been significant. Egypt has intermittently opened and closed the Rafah crossing, affecting the movement of people and goods between Gaza and Egypt.