The development of a distributed application that exhibits both desired functionality as well as performance is a complex task. Therefore, the construction of monitoring tools to assist in the development of complex distributed applications is of great practical significance. For example, monitoring tools can be used to observe the behavior and fine tune the performance. One of the fundamental problems that must be addressed is to ensure that the monitoring tool is able to report the true behavior of an application, that is, it is able to monitor the application non-intrusively. In this paper, we identify the intrusive effects of monitoring on communication in an arbitrary point-to-point network and present the enhanced communication protocol for on-line communication intrusion removal. Our experiments demonstrates that the intrinsic overhead of a distributed system integrated with on-line intrusion removal techniques is 0.43\%, 98.3\% of intrusion on the accumulated number of events and 97.2\% of intrusion on the sequence of event occurrences can be removed successfully.