O NAT é definido no RFC 1631
| Name | Location of Host Represented by Address | IP Address Space in Which Address Exists |
| Inside Local address | Inside the enterprise network | Part of the enterprise IP address space;typically a private IP address |
| Inside Global address | Inside the enterprise network | Part of the public IP address space |
| Outside Local address | In the public Internet; or, outside the enterprise network | Part of the enterprise IP address space; typically a private IP address |
| Outside Global address | In the public Internet; or, outside the enterprise network | Part of the public IP address space |
Ligações:
R1——-s2/1-(outside)R2-(Inside)f0/1———-f0/0-R3
Exemplo 1:
Usando Static NATs
R2(config)#
ip route 0.0.0.0 0.0.0.0 192.168.2.1
interface FastEthernet0/1
ip address 192.168.20.2 255.255.255.0
ip nat inside
interface Serial2/1
ip address 192.168.2.2 255.255.255.0
ip nat outside
ip nat inside source static 1.1.1.1 2.2.2.1
R3(config)#
ip route 0.0.0.0 0.0.0.0 192.168.20.2
interface FastEthernet0/0
ip address 192.168.20.1 255.255.255.0
interface Loopback11
ip address 1.1.1.1 255.255.255.255
interface Loopback14
ip address 1.1.1.4 255.255.255.255
interface Loopback15
ip address 1.1.1.5 255.255.255.255
interface Loopback16
ip address 1.1.1.6 255.255.255.255
interface Loopback17
ip address 1.1.1.7 255.255.255.255
interface Loopback18
ip address 1.1.1.8 255.255.255.255
interface Loopback19
ip address 1.1.1.9 255.255.255.255
interface Loopback20
ip address 1.1.1.10 255.255.255.255
R3#ping 192.168.10.1 so loop11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.10.1, 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 = 36/40/48 ms
R2#sh ip nat trans
Pro Inside global Inside local Outside local Outside global
icmp 2.2.2.1:5 1.1.1.1:5 192.168.10.1:5 192.168.10.1:5
Exemplo 2:
Usando Dynamic NAT
R2(config)#
!Identificar as origens que usam o NAT
access-list 1 permit 1.1.1.4 0.0.0.3
!Criar a pool de IPs
ip nat pool Pool1 2.2.2.4 2.2.2.7 prefix-length 30
ip nat inside source list 1 pool Pool1
R3#ping 192.168.10.1 so loop11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.10.1, 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 = 36/40/48 ms
R3#telnet 192.168.10.1 /source-interface loop15
Trying 192.168.10.1 … Open
R2#sh ip nat statistics
Total active translations: 5 (1 static, 4 dynamic; 2 extended)
Outside interfaces:
Serial2/1
Inside interfaces:
FastEthernet0/1
Hits: 108 Misses: 0
CEF Translated packets: 104, CEF Punted packets: 2
Expired translations: 6
Dynamic mappings:
— Inside Source
[Id: 1] access-list 1 pool Pool1 refcount 4
pool Pool1: netmask 255.255.255.252
start 2.2.2.4 end 2.2.2.7
type generic, total addresses 4, allocated 2 (50%), misses 0
Appl doors: 0
Normal doors: 0
Queued Packets: 0
R2#sh ip nat translations
Pro Inside global Inside local Outside local Outside global
tcp 2.2.2.6:52716 1.1.1.5:52716 192.168.10.1:23 192.168.10.1:23
— 2.2.2.6 1.1.1.5 — —
icmp 2.2.2.5:2 1.1.1.6:2 192.168.10.1:2 192.168.10.1:2
— 2.2.2.5 1.1.1.6 — —
— 2.2.2.1 1.1.1.1 — —
Exemplo 3:
Usando NAT overload
!Overload atraves de uma Pool
access-list 2 permit 1.1.1.8
ip nat pool Pool_GLOBAL 2.2.2.8 2.2.2.11 netmask 255.255.255.252
ip nat inside source list 2 pool Pool_GLOBAL overload
R3#telnet 192.168.10.1 /source-interface loop18
R2#sh ip nat translations
Pro Inside global Inside local Outside local Outside global
— 2.2.2.1 1.1.1.1 — —
tcp 2.2.2.10:39915 1.1.1.8:39915 192.168.10.1:23 192.168.10.1:23
tcp 192.168.2.2:19724 1.1.1.9:19724 192.168.10.1:23 192.168.10.1:23
tcp 192.168.2.2:51357 1.1.1.10:51357 192.168.10.1:23 192.168.10.1:23
Usando NAT overload da interface Outside
!Identificar as origens que usam o NAT
access-list 3 permit 1.1.1.9
access-list 3 permit 1.1.1.10
ip nat inside source list 3 interface Serial 2/1 overload
R3#telnet 192.168.10.1 /source-interface loop19
R3#telnet 192.168.10.1 /source-interface loop20
R2#sh ip nat translations
Pro Inside global Inside local Outside local Outside global
— 2.2.2.1 1.1.1.1 — —
tcp 2.2.2.10:39915 1.1.1.8:39915 192.168.10.1:23 192.168.10.1:23
tcp 192.168.2.2:19724 1.1.1.9:19724 192.168.10.1:23 192.168.10.1:23
tcp 192.168.2.2:51357 1.1.1.10:51357 192.168.10.1:23 192.168.10.1:23