There are passive and hostile mobs in Survival Multiplayer Mode! Only Passive Mobs can spawn in the Peacefull Zone (5 chunks in radius around Spawn Zone ).
Passive Mobs
Chicken
Cow
Pig
Rabbit
Sheep
Ocelot
Wolf
Iron Golem
Hostile Mobs
Zombie
Zombie baby
Spider
Creeper
Charged creeper
Sime
Skeleton
Witch
Enderman