--- System Configuration Dialog --- At any point you may enter a question mark '?' for help. Use ctrl-c to abort configuration dialog at any prompt. Default settings are in square brackets '[]'.
Would you like to enter the initial configuration dialog? [yes]:
如果按y或回车,路由器就会进入设置对话过程。首先你可以看到各端口当前的状况:
First, would you like to see the current interface summary? [yes]: Any interface listed with OK? value "NO" does not have a valid configuration Interface IP-Address OK? Method Status Protocol Ethernet0 unassigned NO unset up up Serial0 unassigned NO unset up up ……… ……… … …… … …
然后,路由器就开始全局参数的设置:
Configuring global parameters:
1.设置路由器名:
Enter host name [Router]:
2.设置进入特权状态的密文(secret),此密文在设置以后不会以明文方式显示:
The enable secret is a one-way cryptographic secret used instead of the enable password when it exists. Enter enable secret: cisco
A 1.0.0.0 到126.0.0.0有效 0.0.0.0 和127.0.0.0保留 B 128.1.0.0到191.254.0.0有效 128.0.0.0和191.255.0.0保留 C 192.0.1.0 到223.255.254.0有效 192.0.0.0和223.255.255.0保留 D 224.0.0.0到239.255.255.255用于多点广播 E 240.0.0.0到255.255.255.254保留 255.255.255.255用于广播
定义一个全局地址池 ip nat pool name start-ip end-ip {netmask netmask prefix-length prefix-length} [type rotary]
建立动态地址翻译 ip nat inside source {list {access-list-number name} pool name [overload] static local-ip global-ip}
指定内部和外部端口 ip nat {inside outside}
路由器的Ethernet 0端口为inside端口,即此端口连接内部网络,并且此端口所连接的网络应该被翻译,Serial 0端口为outside端口,其拥有合法IP地址(由NIC或服务提供商所分配的合法的IP地址),来自网络10.1.1.0/24的主机将从IP地址池c2501中选择一个地址作为自己的合法地址,经由Serial 0口访问Internet。命令ip nat inside source list 2 pool c2501 overload中的参数overload,将允许多个内部地址使用相同的全局地址(一个合法IP地址,它是由NIC或服务提供商所分配的地址)。命令ip nat pool c2501 202.96.38.1 202.96.38.62 netmask 255.255.255.192定义了全局地址的范围。
设置如下:
ip nat pool c2501 202.96.38.1 202.96.38.62 netmask 255.255.255.192 interface Ethernet 0 ip address 10.1.1.1 255.255.255.0 ip nat inside ! interface Serial 0 ip address 202.200.10.5 255.255.255.252 ip nat outside ! ip route 0.0.0.0 0.0.0.0 Serial 0 access-list 2 permit 10.0.0.0 0.0.0.255 ! Dynamic NAT ! ip nat inside source list 2 pool c2501 overload line console 0 exec-timeout 0 0 ! line vty 0 4 end