NAT网络地址翻译

1、.1.21.私有地址（Private Addressing ）2. NAT操作（NAT Operation）3. NAT分类（NAT Class）4. 配置NAT (Configuring NAT) 5. NAT排错（Troubleshooting NAT Configuration）.3Class A:Class B:Class C:1-126128-191192-223127 is lost, why?.41. 公网地址必须被注册 Public Internet addresses must be registered by a company with an Internet autho

2、rity. 2. 私有地址被保留，并可以被任何人使用 Private IP addresses are reserved and can be used by anyone. .5私有地址范围（私有地址范围（Private Address Range）.61. NAT典型工作存根网络的边缘A NAT enabled device typically operates at the border of a stub network. 2. 边界路由器执行NAT功能，将内部私有地址转换成公网可路由的地址。The border gateway router performs the NAT proc

3、ess, translating the internal private address of a host to a public, external routable address. NAT操作（操作（NAT Operation）.71. Inside local address 指定给内部主机使用的地址The IP address assigned to a host on the inside network. 2. Inside global address 从SP或NIC注册的地址，即内部主机地址被NAT转换的外部地址A legitimate IP address assign

4、ed by the NIC or service provider that represents one or more inside local IP addresses to the outside world. 3. Address Pool-NIC或SP分配使用的多个地址IP addresses assigned by the NIC or service provider NAT术语（术语（NAT Terms） .81.静态NAT 静态NAT的特征是内部主机地址被一对一映射到外部主机地址 Static NAT is designed to allow one-to-one mapp

5、ing of local and global addresses. NAT分类（分类（NAT Class）Pc1:10.1.1.1-200.200.200.1Pc2:10.1.1.2-200.200.200.2Pc3:10.1.1.3-Pc4:10.1.1.4-200.200.200.2?X.92. 动态NAT动态NAT的特征是内部主机使用地址池中的公网地址来映射Dynamic NAT is designed to map a private IP address to a public address. Any IP address from a pool of public IP add

6、resses is assigned to a network host. Pc1:10.1.1.1-200.200.200.1Pc2:10.1.1.2-200.200.200.2Pc3:10.1.1.3-Pc4:10.1.1.4-200.200.200.2?.103. 端口复用(PAT) 端口复用的特征是内部多个私有地址通过不同的端口被映射到一个公网地址. 理想状况下，一个单一的IP地址可以使用的端口数为4000个。 NAT分类（分类（NAT Class）.11.12r1(config)#ip nat inside source static 10.1.1.2 200.200.200.3r1

7、(config)#ip nat inside source static 10.1.1.3 200.200.200.4r1(config)#interface f0/0r1(config-if)#ip nat inside r1(config)#int s0/0r1(config-if)#ip nat outside .13r1# debug ip nat IP NAT debugging is on00:11:09: NAT: s=10.1.1.2-200.200.200.3, d=2.2.2.2 4093600:11:09: NAT*: s=2.2.2.2, d=200.200.200.3

8、-10.1.1.2 4093600:11:10: NAT*: s=10.1.1.2-200.200.200.3, d=2.2.2.2 40938r1# sh ip nat translations Pro Inside global Inside local Outside local Outside global- 200.200.200.3 10.1.1.2 - - 200.200.200.4 10.1.1.3 - -.14.15r1(config)#ip nat pool NAT 200.200.200.3 200.200.200.50 netmask 255.255.255.0r1(c

9、onfig)#access-list 1 permit 10.1.1.0 0.0.0.255r1(config)#ip nat inside source list 1 pool NATr1(config)#interface f0/0r1(config-if)#ip nat inside r1(config)#int s0/0r1(config-if)#ip nat outside .16r1# debug ip nat 00:45:40: NAT: s=10.1.1.2-200.200.200.3, d=2.2.2.2 3893000:45:40: NAT*: s=2.2.2.2, d=2

10、00.200.200.3-10.1.1.2 3893000:46:03: NAT: s=10.1.1.3-200.200.200.4, d=2.2.2.2 3896100:46:03: NAT*: s=2.2.2.2, d=200.200.200.4-10.1.1.3 3896100:46:27: NAT: s=10.1.1.4-200.200.200.5, d=2.2.2.2 3899300:46:27: NAT*: s=2.2.2.2, d=200.200.200.5-10.1.1.4 38993.17r1#sh ip nat translations Pro Inside global

11、Inside local Outside local Outside global- 200.200.200.3 10.1.1.2 200.200.200.4 10.1.1.3 - 200.200.200.5 10.1.1.4 - -r1#clear ip nat translation *r1#sh ip nat translations .18如果我们已经用完地址池中的地址，将发生什么事情？ If we have used all available public address in pool, what will happen in next translation?.1901:07:

12、36: NAT: translation failed (A), dropping packet s=10.1.1.3 d=2.2.2.2r1#01:07:37: NAT: translation failed (A), dropping packet s=10.1.1.3 d=2.2.2.2以上结果表明NAT转换失败，并将丢包.20.21r1(config)#ip nat pool NAT 200.200.200.3 200.200.200.50 netmask 255.255.255.0r1(config)#access-list 1 permit 10.1.1.0 0.0.0.255r1(config)#ip nat inside source list 1 pool NAT overloadr1(config)#interface f0/0r1(config-if)#ip nat inside r1(config)#int s0/0r1(config-if)#ip nat outside r1(config)#ip route 0.0.0.0 0.0.0.0 200.200.200.2.22r1#sh ip nat