@Mehdi236,
Neither one is.
Did someone disconnect the internet?
And here is the difference between active and passive forms because I can see it's not being addressed here.
Active - the subject of the sentence performs the activity.
Passive - the subject of the sentence has the activity performed on him/her/it. Often the predicate from the active form comes first, and often a form of the verb 'to be' is a part of passive voice (although not always).
For example -
Active: I saw a butterfly.
Passive: A butterfly was seen by me.
Active: She ate all the pie.
Passive: All of the pie was eaten by her.
Active: Did someone disconnect the internet?
Passive: Was the internet disconnected by someone?
Keep in mind that understanding active and passive voice is not confined to just learning English. You can have passive voice in other languages.