NAT的术语与转换表
- NAT包含4类地址
NAT的转换条目
- 简单转换条目
- 扩展转换条目
静态转换和动态转换
NAT的特性
优点:
- 节省公有合法IP地址
- 处理地址重叠
- 增强灵活性
- 安全性
缺点:
- 延迟增大
- 配置和维护的复杂性
- 不支持某些应用,可以通过静态NAT映射来避免
下面我们来操作以下NAT地址转换的实验,拓扑如下:
SW1配置:
######划分vlan
[SW1]vlan bat 10 20 30 40 //创建vlan
[SW1]int g0/0/1
[SW1-GigabitEthernet0/0/1]port link-type access
[SW1-GigabitEthernet0/0/1]port default vlan 10
[SW1-GigabitEthernet0/0/1]un sh
[SW1-GigabitEthernet0/0/1]int g0/0/2
[SW1-GigabitEthernet0/0/2]port link-type access
[SW1-GigabitEthernet0/0/2]port default vlan 20
[SW1-GigabitEthernet0/0/2]un sh
[SW1-GigabitEthernet0/0/2]int g0/0/3
[SW1-GigabitEthernet0/0/3]port link-type access
[SW1-GigabitEthernet0/0/3]port default vlan 30
[SW1-GigabitEthernet0/0/3]un sh
[SW1-GigabitEthernet0/0/3]int g0/0/4
[SW1-GigabitEthernet0/0/4]port link-type access
[SW1-GigabitEthernet0/0/4]port default vlan 20
[SW1-GigabitEthernet0/0/4]un sh
[SW1-GigabitEthernet0/0/4]int g0/0/5
[SW1-GigabitEthernet0/0/5]port link-type access
[SW1-GigabitEthernet0/0/5]port default vlan 40
[SW1-GigabitEthernet0/0/5]un sh
######配置vlanif,网关
[SW1-GigabitEthernet0/0/6]int vlanif 10
[SW1-Vlanif10]ip add 192.168.10.1 24
[SW1-Vlanif10]int vlanif 20
[SW1-Vlanif20]ip add 192.168.20.1 24
[SW1-Vlanif20]int vlanif 30
[SW1-Vlanif30]ip add 192.168.30.1 24
[SW1-Vlanif30]int vlanif 40
[SW1-Vlanif40]ip add 11.0.0.2 24
######配置默认路由出去
[SW1]ip route-static 0.0.0.0 0.0.0.0 11.0.0.1
R1配置:
######配置端口地址
[R1]int g0/0/0
[R1-GigabitEthernet0/0/0]ip add 11.0.0.1 24
[R1-GigabitEthernet0/0/0]un sh
[R1-GigabitEthernet0/0/0]int g0/0/1
[R1-GigabitEthernet0/0/1]ip add 12.0.0.1 24
[R1-GigabitEthernet0/0/1]un sh
[R1-GigabitEthernet0/0/1]q
######配置静态路由回程
[R1]ip route-static 192.168.10.0 255.255.255.0 11.0.0.2
[R1]ip route-static 192.168.20.0 255.255.255.0 11.0.0.2
[R1]ip route-static 192.168.30.0 255.255.255.0 11.0.0.2
######静态NAT:一个私网IP地址对应一个公网IP地址
[R1]nat static global 8.8.8.8 inside 192.168.10.10 //全局模式下
[R1]int g0/0/1
[R1-GigabitEthernet0/0/1]nat static enable //在外网接口上启动nat static功能
######配置默认路由出去
[R1]ip route-static 0.0.0.0 0.0.0.0 12.0.0.2
######配置回环接口的静态路由
ip route-static 114.114.114.114 255.255.255.255 12.0.0.2
#######动态NAT:多个私网IP地址对应多个公网IP地址
[R1]nat address-group 1 212.0.0.100 212.0.0.200 //新建为1的nat地址池
[R1]acl 2000 // ac1编号
[R1-acl-basic-2000]rule permit source 192.168.20.0 0.0.0.255 //建立规则,20网段,反掩码
[R1-acl-basic-2000]int g0/0/1 //进入外网接口
[R1-GigabitEthernet0/0/1]nat outbound 2000 address-group 1 no-pat
######EasyIp:多个私网IP地址对应外网口公网IP地址(12.0.0.1)
[R1]acl 3000
[R1-acl-adv-3000]rule permit ip source 192.168.30.0 0.0.0.255
[R1-acl-basic-2000]int g0/0/1 //进入外网接口
[R1-GigabitEthernet0/0/1]nat outbound 3000
R2配置
######配置端口地址
[R2]int g0/0/0
[R2-GigabitEthernet0/0/0]ip add 12.0.0.2 24
[R2-GigabitEthernet0/0/0]un sh
[R2-GigabitEthernet0/0/0]int g0/0/1
[R2-GigabitEthernet0/0/1]ip add 13.0.0.1 24
[R2-GigabitEthernet0/0/1]un sh
[R2]int lo
[R2]int LoopBack 0
[R2-LoopBack0]ip add 114.114.114.114 32
[R2-LoopBack0]q
######配置静态路由回程
[R2]ip route-static 8.8.8.8 255.255.255.255 12.0.0.1
[R2]ip route-static 212.0.0.0 255.255.255.255 12.0.0.1
实验验证Nat转换: