Router 2821

interface Loopback0
 ip address 1.1.1.1 255.255.255.255
 ip nat inside
 ip virtual-reassembly
!
interface GigabitEthernet0/0
 ip address 192.1.1.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 duplex full
 speed 100
!
interface Serial0/2/0
 ip address 192.10.10.2 255.255.255.252
 ip nat outside
 ip virtual-reassembly
!
ip nat inside source list Natting interface Serial0/2/0 overload
!
ip access-list extended Natting
 permit ip host 2.2.2.2 any
 permit ip 192.2.1.0 0.0.0.255 any
!

C2821#ping 1.1.1.1 source 2.2.2.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
Packet sent with a source address of 2.2.2.2
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/20/32 ms
C2821#sh ip nat translations
Pro Inside global         Inside local          Outside local         Outside global
icmp 192.10.10.2:13       2.2.2.2:13            1.1.1.1:13            1.1.1.1:13
C2821#sh ip nat statistics
Total active translations: 1 (0 static, 1 dynamic; 1 extended)
Outside interfaces:
  Serial0/2/0
Inside interfaces:
  GigabitEthernet0/0, Loopback0
Hits: 10  Misses: 0
CEF Translated packets: 0, CEF Punted packets: 157938
Expired translations: 1
Dynamic mappings:
-- Inside Source
[Id: 1] access-list Natting interface Serial0/2/0 refcount 1
Appl doors: 0
Normal doors: 0
Queued Packets: 0

Router 3845

interface Loopback0
 ip address 1.1.1.1 255.255.255.255
 ip nat inside
 ip virtual-reassembly
!
interface GigabitEthernet0/0
 ip address 192.1.1.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 duplex full
 speed 100
 media-type rj45
!
interface Serial0/1/0
 ip address 192.10.10.1 255.255.255.252
 ip nat outside
 ip virtual-reassembly
 clock rate 128000
!
router eigrp 100
 network 1.1.1.1 0.0.0.0
 network 192.1.1.0
 network 192.10.10.0 0.0.0.3
 auto-summary
!
ip nat inside source list Nat_Traffic interface Serial0/1/0 overload
!
ip access-list extended Nat_Traffic
 permit ip host 1.1.1.1 any
 permit ip 192.1.1.0 0.0.0.255 any
!
C3845#ping 192.2.1.2 source 1.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.2.1.2, timeout is 2 seconds:
Packet sent with a source address of 1.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms
C3845#SH IP NAT TRANslations
Pro Inside global         Inside local          Outside local         Outside global
icmp 192.10.10.1:19       1.1.1.1:19            192.2.1.2:19          192.2.1.2:19
C3845#sh ip nat statistics
Total active translations: 1 (0 static, 1 dynamic; 1 extended)
Outside interfaces:
  Serial0/1/0
Inside interfaces:
  GigabitEthernet0/0, Loopback0
Hits: 10  Misses: 0
CEF Translated packets: 5, CEF Punted packets: 0
Expired translations: 0
Dynamic mappings:
-- Inside Source
[Id: 1] access-list Nat_Traffic interface Serial0/1/0 refcount 1
Appl doors: 0
Normal doors: 0
Queued Packets: 0