Bukkit

Enabled permissions and set the permission node needed.
permissions:

1. warning - to change from true/false false/true
   
2. you must restart your server to take effect
   enabled: false
   required: stun.player

Enable pvp by setting 'active: true'
'random: true' will make stun durations random from 1 to 'duration'
'chance' is the % likelihood of a stun occurring
pvp:
active: false
random: false
duration: 3
chance: 5

'mob_active' determines if mobs can stun
'mob_random' acts as random above

You can also turn on or off each individual mob type and configure it individually.
mob_active: true
mob_random: true

mobs:
blaze:
active: false
duration: 3
chance: 10