Core part of state-of-the-art mobile networks is composed of several standard elements like GGSN (Gateway General Packet Radio Service Support Node), SGSN (Serving GPRS Support Node), F5 or MSP (Multi Service Proxy). Each node handles network traffic from a slightly different perspective, and with various goals. In this paper, the authors will focus only on the MSP, its key features and especially on related security issues. MSP handles all HTTP traffic in the mobile network and therefore it is a suitable point for the implementation of different optimization functions, e.g. to reduce the volume of data generated by YouTube or similar HTTP-based service.