1、掌握 6to4 隧道的配置方法（GRE）

拓扑图：

配置各路由器的IPv4地址和IPv6地址，测试IPv4地址互连可达。

同时为IPv4网络配置RIP协议或者其它路由协议，保证IPv4网络可路由性，自行决定协议，能用就行，我这里用的是默认路由。

在R1上ping R3的S1/0接口：

R1#ping 192.168.2.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.2.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 16/52/140 ms

在R1和R3上配置GRE隧道，用于解决IPv6网络相互访问需求：

R1(config)#int tunnel 1   ---->启用GRE隧道接口1

R1(config-if)#ipv6 add 2001:ab1:0:2::1/64  ---->配置隧道的IPv6地址

R1(config-if)#tunnel source 192.168.1.1    ---->配置隧道源端口

R1(config-if)#tunnel destination 192.168.2.2 ---->配置隧道目标地址，必须可达，必须存在于IPv4路由表中

R1(config-if)#tunnel mode ipv6ip     ----->配置隧道模式为IPv6 over ip模式，可选配置

R1(config-if)#no sh

R1(config-if)#exit

R3(config)#int tunnel 1

R3(config-if)#ipv6 add 2001:ab1:0:2::2/64

R3(config-if)#tunnel source s1/0   ---->可以使用本地端口号描述隧道源

R3(config-if)#tunnel destination 192.168.1.1

R3(config-if)#tunnel mode ipv6ip

R3(config-if)#no sh

R3(config-if)#exit

在R1或R3上使用ping命令测试隧道配置：

R1#ping 2001:ab1:0:2::2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:AB1:0:2::2, timeout is 2 seconds:

!!!!!   ----->通~~~

Success rate is 100 percent (5/5), round-trip min/avg/max = 20/63/112 ms

查看R3的IPv6路由表：

R3#show ipv6 rout

IPv6 Routing Table - 5 entries

Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP

       U - Per-user Static route, M - MIPv6

       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary

       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2

       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2

       D - EIGRP, EX - EIGRP external

C   2001:AB1:0:2::/64 [0/0]

     via ::, Tunnel1

L   2001:AB1:0:2::2/128 [0/0]

     via ::, Tunnel1         ----->指出可以通过隧道直接到达R1

C   2001:AB1:0:3::/64 [0/0]

     via ::, Loopback0

L   2001:AB1:0:3::1/128 [0/0]

     via ::, Loopback0

L   FF00::/8 [0/0]

     via ::, Null0

添加IPv6的静态路由：

R1(config)#ipv6 route 2001:ab1:0:3::/64 2001:ab1:0:2::2   ---->下一跳指定为隧道的对端地址

R3(config)#ipv6 route ::/0 2001:ab1:0:2::1                ---->默认路由

测试IPv6网络连通性：

R3#ping 2001:ab1:0:c::1 so 2001:ab1:0:3::1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:AB1:0:C::1, timeout is 2 seconds:

Packet sent with a source address of 2001:AB1:0:3::1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/52/96 ms

R3#ping 2001:ab1:0:9::1 so 2001:ab1:0:3::1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:AB1:0:9::1, timeout is 2 seconds:

Packet sent with a source address of 2001:AB1:0:3::1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 8/96/168 ms

R3#ping 2001:ab1:0:b::1                  

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:AB1:0:B::1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 8/78/176 ms

R3#ping 2001:ab1:0:a::1                  

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 2001:AB1:0:A::1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/60/144 ms

一切正常。