NAT和GRE tunnel在思科路由器上的实现

 

Topology:

Client --- Router(NAT) ===GRE tunnel=== Router --- Server

Client:  90.1.0.8

NAT Router outside: 90.1.0.1

Server 1: 100.100.100.142

Server 2: 100.100.100.162

Server GW: 100.100.100.1

关注点：

1. outside必然是放在client的GW这一侧，这无可争议

2. inside应该是放在tunnel上，而不是出口的物理interface上，在这里是Gi0/0/1

NAT Router configuration:

ASR1004-5#sh run inter gi 0/0/0
Load for five secs: 0%/0%; one minute: 0%; five minutes: 0%
No time source, *05:56:27.549 UTC Tue Aug 5 2014

Building configuration...

Current configuration : 119 bytes
!
interface GigabitEthernet0/0/0
 ip address 90.1.0.1 255.255.255.0
 ip nat outside
 negotiation auto
 cdp enable
end

ASR1004-5#sh run inter gi 0/0/1
Load for five secs: 0%/0%; one minute: 0%; five minutes: 0%
No time source, *05:56:28.603 UTC Tue Aug 5 2014

Building configuration...

Current configuration : 108 bytes
!
interface GigabitEthernet0/0/1
 ip address 202.202.202.5 255.255.255.0
 negotiation auto
 cdp enable
end

ASR1004-5#sh run inter tunnel 1
Load for five secs: 0%/0%; one minute: 0%; five minutes: 0%
No time source, *05:56:38.647 UTC Tue Aug 5 2014

Building configuration...

Current configuration : 149 bytes
!
interface Tunnel1
 ip address 192.168.0.5 255.255.255.0
 ip nat inside
 tunnel source GigabitEthernet0/0/1
 tunnel destination 202.202.202.15
end

ASR1004-5#sh run | in ip nat
 ip nat inside
 ip nat outside
ip nat inside source static 100.100.100.142 90.1.0.14
ip nat inside source static 100.100.100.162 90.1.0.16

Server GW Router Configuration:

ASR1002-15#sh run inter gi 0/0/0
Load for five secs: 1%/0%; one minute: 1%; five minutes: 1%
Time source is NTP, *13:49:37.402 CST Tue Aug 5 2014

Building configuration...

Current configuration : 122 bytes
!
interface GigabitEthernet0/0/0
 ip address 202.202.202.15 255.255.255.0
 negotiation auto
 ipv6 enable
 cdp enable
end

ASR1002-15#sh run inter gi 0/0/1
Load for five secs: 1%/0%; one minute: 1%; five minutes: 1%
Time source is NTP, *13:49:40.811 CST Tue Aug 5 2014

Building configuration...

Current configuration : 121 bytes
!
interface GigabitEthernet0/0/1
 ip address 100.100.100.1 255.255.255.0
 negotiation auto
 ipv6 enable
 cdp enable
end

ASR1002-15#sh run inter tunnel 1
Load for five secs: 1%/0%; one minute: 1%; five minutes: 1%
Time source is NTP, *13:49:48.747 CST Tue Aug 5 2014

Building configuration...

Current configuration : 134 bytes
!
interface Tunnel1
 ip address 192.168.0.15 255.255.255.0
 tunnel source GigabitEthernet0/0/0
 tunnel destination 202.202.202.5
end

ASR1002-15#