Network Configuration

You are all right to a certain extnet. It really depends on what level of study we are talking about. To develop small or non critical softwares or to administrate non critical networks, we don't need to be very good at these two subject to study IT. For now, these are usually needed for IT markets in Cambodia. Physics (specifically electronics) are required for computer engineers (people who design, e.g., CPU). For critical systems, like softwares to control airplane, techniques in maths are used, e.g., to prove that the softwares are correct. Even in Networks, we use techniques in maths to prove correctness of protocols. Cryptography, which also concerns maths, is used to transmit data securely on networks.But for the need of our country right now, we don't need to be very good at these two subject to be able study IT. As already mentioned in the comments, it depends on our efforts and commitments. Everybody can study IT if they really like it.