SHAFAQNA – The Grand Ayatollah Khamenei answered a question about those places providing internet and the Haram use of it by customers.
Question: If a person owns an internet cafe and is aware that some customers use the place to enter inappropriate sites and chat rooms, what is the ruling regarding the owner and the income earned (considering the mentioned conditions)?
The Grand Ayatollah Khamenei: If the owner is sure that the customer is using the facilities for Haram purposes, is not allowed and there is problem with this kind of income. But if (the owner) is in doubt that the customer is using it (internet) for Haram purposes, there is no problem.
Source: Persian SHAFAQNA