Now that your checking is complete, it s time to put the machine back on the network. Plug the Ethernet cable(s) back into your network card(s). If you used the method of shutting down the interface manually with the ifconfig command, your machine should have come back on the network after rebooting in step 5. If the interface is not back up, use a tool like netconfig to correctly configure your network interface(s). The network device could be brought up manually, but the configuration would not be persistent through a reboot.
The quickest way to test whether you are back on the network is to ping the gateway. If you are not sure what your gateway IP is, type ip route and take the IP address that is on the default line. You may need to add a -b to the ping line; the command will tell you if it is necessary. Type ping gatewayIP , as in ping 192.168.1.1 . If you are back on the network, you should get messages showing the time it takes the packets to reach your gateway.
Congratulations, you are done hardening your network services. Go on to Chapter 3 and harden the security of your network interface.