NAT: Network Address Translation, a serious shortage of IP addresses resolve
Solution: Use internal address on the internal network, the internal address is translated by NAT into valid public IP address, and then connect to the Internet
NAT FIG one: 
Rl: FA1 / 0 12.1.1.1 Fa0 / 0 192.160.1.254
SW1: VLAN1 192.160.1.100
PC0: 192.160.1.1
PC1: 12.1.1.3 
turn on the switch SW1 telnet remote login service and set a password.
SW1>
Line vty 0 4 0-4 entering virtual port
password xxwj password xxwj
the Login to open and save
Exit
enable Secret xxwj set a global cipher text password xxwj
hostname named SW1 switch SW1 changes 
do nat on the router
R1>
ip nat static Inside Source 192.160.1.100 12.1.1.100 establish internal static NAT a local address 192.160.1.100 global address 12.1.1.100 and the internal
interface fa 1/0
IP NAT outside the interface fa 1/0 flag to interface the external network (outside the specified interface out)
fa 0/0 interface
IP NAT inside the interface fa 0/0 labeled internal network interface (specified incoming interface)
PC1 now used to test remote connection switch SW1, IP address is translated address 12.1.1.100
PC1> the Telnet 12.1.1.100
passwod: xxwj above set too remote login password xxwj
SW1> enable
passwod: xxwj above set too login password xxwj
Show ip after interface brief check the IP address was found, SW1 switch only 192.168.1.100 address, this address is logged out of the static converter. 
You can view displays events by looking at the conversion router
R1> enable
Show Translations' show ip NAT conversion activity
display 23 port because using a remote login, it is TCP23