In this chapter, we have looked at the configuration and the working details of setting up a packet filter and an application gateway. We have looked at the advantages and disadvantages of the application gatewaying and packet filtering methods of firewalling. We have also presented a firewalling solution that combines the two types of firewalling mechanisms and promises better results. The combined firewall solution seems to present ``the best of both worlds''. All the advantages of the packet filtering and application proxying methods of firewalling are preserved with the combined solution. The disadvantages of each firewalling paradigm are reduced by the ``protection'' one component of the combined solution provides to the other. After running our firewall with a combined configuration firewall for more than six months, without security incidents, we are convinced that it is one of the best, if not the best, firewalling solution that exists.