How do I easily dispatch a ghast in Minecraft?
Solution 1:
Ghasts can be tricky, but manageable if you know what you're doing. Personally, I prefer to use a bow to kill ghasts. They don't have a lot of hitpoints, and an unenchanted bow can kill a ghast in 2 shots according to the wiki. Another option is to reflect their fireball, which is an instant kill and an achievement, but this is riskier, and more difficult.
Another thing to keep in mind is that ghast fireballs cause a small explosion, which is enough to destroy some blocks like netherrack, sandstone, dirt, and can even put out your nether portal. But, it is not strong enough to destroy cobblestone. The first thing I do when entering the nether is construct a stone shelter around my portal to at least keep me from getting trapped in the nether.