방화벽이 · 방화벽을
firewall
Example
방화벽을 설정하면 외부의 공격을 막을 수 있어요.
Setting up a firewall can block outside attacks.
Word parts
방 prevent+화 fire+벽 wall
Literally 'wall that prevents fire' — first a building term, then a computer one.
Good to know
Don't confuse 방화 'fire prevention' with its homonym 방화 'arson'.
Related words