Real-time kinematic (RTK) is the most popular GNSS-based precise positioning technique that is widely used in many navigation and control systems. RTK is a relative positioning method, which takes advantage of pseudo-range and carrier-phase observations received at a mobile GNSS receiver (rover) and a fixed base station. After fixing the integer ambiguities, the carrier-phase observables can be utilized for precise positioning such that RTK can estimate the rover's position with centimeter-level accuracy. In order to produce instantaneous location information, correction data needs to be effectively transferred from the base station to the rover via a communication link. Various ways of correction information transmission have been proposed over the years. In this work, we utilize the Networked Transport of RTCM via Internet Protocol (NTRIP) for data transmission. We establish the connection between the base station and the rover through a virtual private network (VPN), which allows the rover to communicate with the base station using a local IP address, regardless of the nature of the Internet connection on both sides. To study the impact of the quality of the Internet connection, especially with respect to latency, we evaluate the performance of RTK positioning under different Internet connection conditions. We carry out experiments using commercial GNSS RTK products.