The problems to network security posed in chapter 4 have solutions. These solutions have been presented both theoretically and practically. A ``global'' solution, the firewall, to the problems of network security has been presented in theory. The firewall has then been applied as a solution to some of the problems in network security. Other solutions presented include hardware solutions and encryption. For more information on firewalls, the interested reader is referred to [7]. The next chapter shows examples of firewall use in solving security problems that exist on the host and the network.