Abstract: To improve security in a networking environment an external network 102 is connected through an outside host 104. This host 104 implements a first connection program 112 for providing network security. Further, the outside host is connected to an inside host 106 via a dedicated transmission path 116. The inside host implements a second connection program 114 as well. The first and second connection programs 112 and 114 each comprises a program at the application level and a driver program for driving the dedicated communication path. By virtue of restricted communication between the two connection programs only, it is possible to prevent invasion from the outside world. Further, it is also possible to prevent access to another portion in the system.