网络工程 - NAT 转换 IP 使用情况 - 吾爱随笔录

我是 cisco 的新手，目前正在学习认证，这只是我实践所学知识的方式。目前我处于停滞状态，因为我似乎无法理解正在发生的事情，或者我的 NAT 基础知识是离开。无论如何，请参考我通过 Packet Tracer 创建的拓扑

CR 运行配置

!
!
!
interface GigabitEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 ip nat inside
 duplex auto
 speed auto
!
interface GigabitEthernet0/1
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface GigabitEthernet0/2
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface Serial0/3/0
 ip address 205.112.2.1 255.255.255.252
 ip nat outside
!
interface Serial0/3/1
 no ip address
 clock rate 2000000
 shutdown
!
interface Vlan1
 no ip address
 shutdown
!
ip nat pool mypool 172.16.2.1 172.16.2.31 netmask 255.255.255.224
ip nat inside source list 50 pool mypool overload
ip classless
!
ip flow-export version 9
!
!
access-list 50 permit 192.168.1.0 0.0.0.255
!
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
 login
!
!
!
end

ISP 运行配置

interface GigabitEthernet0/0
 ip address 210.125.35.1 255.255.255.0
 duplex auto
 speed auto
!
interface GigabitEthernet0/1
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface GigabitEthernet0/2
 no ip address
 duplex auto
 speed auto
 shutdown
!
interface Serial0/3/0
 ip address 205.112.2.2 255.255.255.252
 clock rate 64000
!
interface Serial0/3/1
 no ip address
 clock rate 2000000
 shutdown
!
interface Vlan1
 no ip address
 shutdown
!
ip classless
ip route 0.0.0.0 0.0.0.0 205.112.2.1 
!
ip flow-export version 9
!
!
!
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
 login
!
!
!
end

现在，CR是我的公司路由器，通过串行接口连接，这也是我放置 NAT 配置的地方。ISP's 只是为了 ping 目的返回 CR 的静态路由。

我为验证此设置所做的工作是通过pingPC0/PC1/PC2 到 Server0，但是它无法访问（是的，可以理解，因为 CR 没有路由到 210.125.35.0 网络）但考虑到在该路由器上配置了 NAT，我希望它可以通过公共IP并路由它，此时我真的很困惑。现在我做的另一项测试是ping对 ISP 路由器上的 205.112.2.2 接口进行翻译（通过确认show ip nat translation）。在这一点上，我确定我错过了一些东西，因为我在这一点上真的很困惑..

有人可以帮我清理一下吗？

编辑

正如@Ron Maquin 所说，这是一个路由问题，我添加了一个默认路由，但是当我从 PC0 进行连续 ping 时，nat 转换正在增加。据我所知，它只会将分配的端口重用于转换后的 IP（在本例中为 PC0）。如果我错了，请纠正我，另请参阅show ip nat translation输出

CR#show ip nat translations 
Pro  Inside global     Inside local       Outside local      Outside global
icmp 172.16.2.1:27     192.168.1.2:27     210.125.35.110:27  210.125.35.110:27
icmp 172.16.2.1:28     192.168.1.2:28     210.125.35.110:28  210.125.35.110:28
icmp 172.16.2.1:29     192.168.1.2:29     210.125.35.110:29  210.125.35.110:29
icmp 172.16.2.1:30     192.168.1.2:30     210.125.35.110:30  210.125.35.110:30
icmp 172.16.2.1:31     192.168.1.2:31     210.125.35.110:31  210.125.35.110:31
icmp 172.16.2.1:32     192.168.1.2:32     210.125.35.110:32  210.125.35.110:32
icmp 172.16.2.1:33     192.168.1.2:33     210.125.35.110:33  210.125.35.110:33
icmp 172.16.2.1:34     192.168.1.2:34     210.125.35.110:34  210.125.35.110:34
icmp 172.16.2.1:35     192.168.1.2:35     210.125.35.110:35  210.125.35.110:35
icmp 172.16.2.1:36     192.168.1.2:36     210.125.35.110:36  210.125.35.110:36
icmp 172.16.2.1:37     192.168.1.2:37     210.125.35.110:37  210.125.35.110:37
icmp 172.16.2.1:38     192.168.1.2:38     210.125.35.110:38  210.125.35.110:38
icmp 172.16.2.1:39     192.168.1.2:39     210.125.35.110:39  210.125.35.110:39
icmp 172.16.2.1:40     192.168.1.2:40     210.125.35.110:40  210.125.35.110:40
icmp 172.16.2.1:41     192.168.1.2:41     210.125.35.110:41  210.125.35.110:41
icmp 172.16.2.1:42     192.168.1.2:42     210.125.35.110:42  210.125.35.110:42
icmp 172.16.2.1:43     192.168.1.2:43     210.125.35.110:43  210.125.35.110:43
icmp 172.16.2.1:44     192.168.1.2:44     210.125.35.110:44  210.125.35.110:44
icmp 172.16.2.1:45     192.168.1.2:45     210.125.35.110:45  210.125.35.110:45
icmp 172.16.2.1:46     192.168.1.2:46     210.125.35.110:46  210.125.35.110:46
icmp 172.16.2.1:47     192.168.1.2:47     210.125.35.110:47  210.125.35.110:47