R1：

interface Serial0/0
 ip address 10.1.1.1 255.255.255.0
 ip nat outside                                    //设置为外部连接端口
 ip virtual-reassembly
 serial restart-delay 0
!
interface FastEthernet1/0
 ip address 192.1.1.1 255.255.255.0
 ip nat inside                                   //设置为内部连接端口
 ip virtual-reassembly
 duplex auto
 speed auto
!
interface FastEthernet2/0
 ip address 192.1.2.1 255.255.255.0
 ip nat inside                                        //设置为内部连接端口
 ip virtual-reassembly
 duplex auto
 speed auto
!

R2：

interface Serial0/0
 ip address 10.1.1.2 255.255.255.0
 ip nat outside                                  //设置为外部连接端口
 ip virtual-reassembly
 serial restart-delay 0
!
interface Serial0/1
 ip address 172.16.1.2 255.255.255.0
 serial restart-delay 0
!
interface FastEthernet1/0
 ip address 172.1.1.1 255.255.255.0
 ip nat inside                                  //设置为内部连接端口
 ip virtual-reassembly
 duplex auto
 speed auto
!
interface FastEthernet2/0
 ip address 172.1.2.1 255.255.255.0
 ip nat inside                                 //设置为内部连接端口
 ip virtual-reassembly
 duplex auto
 speed auto

pc1：

interface FastEthernet0/0
 ip address 192.1.1.2 255.255.255.0
 no ip route-cache
 duplex auto
 speed auto
!
ip default-gateway 192.1.1.1

pc2：

interface FastEthernet0/0
 ip address 192.1.2.2 255.255.255.0
 no ip route-cache
 duplex auto
 speed auto
!
ip default-gateway 192.1.2.1

pc3：

interface FastEthernet0/0
 ip address 172.1.1.2 255.255.255.0
 no ip route-cache
 duplex auto
 speed auto
!
ip default-gateway 172.1.1.1

pc4：

interface FastEthernet0/0
 ip address 172.1.2.2 255.255.255.0
 no ip route-cache
 duplex auto
 speed auto
!
ip default-gateway 172.1.2.1

首先配置一对一的静态NAT

R1(config)#ip nat inside source static 192.1.1.2 10.1.1.3                    //静态一对一转换
R1(config)#ip nat inside source static 192.1.2.2 10.1.1.4

R2(config)#ip nat inside source static 172.1.1.2 10.1.1.5
R2(config)#ip nat inside source static 172.1.2.2 10.1.1.6

pc1#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/48/172 ms

pc1#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/69/164 ms

pc2#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/40/144 ms
pc2#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/63/144 ms

看一下转换的情况

R1#sh ip nat translations
Pro Inside global      Inside local       Outside local      Outside global
--- 10.1.1.3           192.1.1.2          ---                ---
icmp 10.1.1.4:11       192.1.2.2:11       10.1.1.2:11        10.1.1.2:11
--- 10.1.1.4           192.1.2.2          ---                ---
 
R1#sh ip nat statistics                                 ip nat的基本状态              
Total active translations: 3 (2 static, 1 dynamic; 1 extended)
Outside interfaces:
  Serial0/0
Inside interfaces:
  FastEthernet1/0, FastEthernet2/0
Hits: 49  Misses: 11
CEF Translated packets: 56, CEF Punted packets: 8
Expired translations: 10
Dynamic mappings:
Queued Packets: 0

下面配置动态NAT转换

R1(config)#access-list 1 permit 192.1.1.0 0.0.0.255
R1(config)#access-list 1 permit 192.1.2.0 0.0.0.255         //配置访问列表

R1(config)#ip nat pool cisco 10.1.1.3 10.1.1.4 prefix-length 24       //配置NAT的地址池


R1(config)#ip nat inside source list 1 pool cisco       //将内网地址动态转换

pc1#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/45/136 ms
pc1#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/76/224 ms

pc2#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/78/244 ms
pc2#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/52/160 ms

看一下转换情况，转换成功

R1#sh ip nat translations
Pro Inside global      Inside local       Outside local      Outside global
--- 10.1.1.3           192.1.1.2          ---                ---
icmp 10.1.1.4:20       192.1.2.2:20       10.1.1.2:20        10.1.1.2:20
--- 10.1.1.4           192.1.2.2          ---                ---
最后配置一下PAT

R2(config)#access-list 1 permit 172.1.1.0 0.0.0.255
R2(config)#access-list 1 permit 172.1.2.0 0.0.0.255 

R2(config)#ip nat pool onlyone 10.1.1.10 10.1.1.10 prefix-length 24

R2(config)#ip nat inside source list 1 pool onlyone overload    //转换为超载地址

pc3#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/64/216 ms
pc3#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/40/128 ms

pc4#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/70/196 ms
pc4#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/46/124 ms

看一下PAT的转换情况，同一个超载地址，用不同的端口

R2#sh ip nat translations
Pro Inside global      Inside local       Outside local      Outside global
icmp 10.1.1.10:4       172.1.1.2:4        10.1.1.1:4         10.1.1.1:4
icmp 10.1.1.10:5       172.1.2.2:5        10.1.1.1:5         10.1.1.1:5