1. private ip
10.0.0.0 ~ 10.255.255.255
172.16.0.0~ 172.31.255.255
192.168.0.0~192.168.255.255
2. Cisco用術語內部區域(inside local)表示private IP address,用術語Inside Global表示公共IP Address
3. 動態NAT與靜態NAT相同之處為NAT Router在inside local and inside globel之間也建立一對一的對應,並在封包進、出內部網路時轉譯IP address。
4. 動態NAT為所有可能的內部全域位址開闢一個address pool,並定義比對標準以確定轉譯哪個內部區域IP address。
5. route table的動態表格項目只在資料流傳送時存在,亦可透過clear ip nat translation命令手動清除route table的動態表格項目。
6. NAT 超載特性,也稱為Port address translation(PAT)。
7. setting static NAT
a. ip nat inside ==>設定NAT內部介面
b. ip nat outside ==>設定NAT外部介面
c. ip nat inside source static inside-local inside-global ==>設定靜態對應
ex.
interface Ethernet0/0
ip address 10.1.1.3 255.255.255.0
ip nat inside
interface serial0/0
ip address 200.1.1.251 255.255.255.0
ip nat outside
ip nat inside source static 10.1.1.2 200.1.1.2
ip nat inside source static 10.1.1.3 200.1.1.3
8. show ip nat translations ==>可查看NAT狀態
show ip nat statistics ==>查看nat 統計數據
9. setting dynamic NAT
a. ip nat inside
b. ip nat outside
c. setting ACL
d. ip nat pool name first-address last-address mask subnet-mask
e. ip nat source list acl-number pool pool-name
ex.
interface Ethernet0/0
ip address 10.1.1.3 255.255.255.0
ip nat inside
interface serial0/0
ip address 200.1.1.251 255.255.255.0
ip nat outside
ip nat pool fred 200.1.1.1 2000.1.1.2 netmask 255.255.255.252
ip nat inside source list 1 pool fred
access-list 1 premit 10.1.1.2
access-list 1 premit 10.1.1.1
10. debug ip nat 可檢視nat運作狀況:獲得NAT轉譯過IP address的各個封包的日誌訊息
11. setting PAT
a. ip nat inside
b. ip nat outside
c. setting ACL
d. ip nat source list acl-number interface name/number overload