題意如下：
1、路由器A位於ISP。210.31.197.94是服務商提供的網關。
2、路由器B與C位於學校內部，在B路由器上做了NAT，其中F0是NAT的外部口，S0是NAT的內部口
3、最終目的實現PC到A路由器F1口能夠連通
4、部分配置如下（使用OSPF完成的連接）
路由器B配置：
B#sh run
interface FastEthernet0
ip address 210.31.197.93 255.255.255.224
ip nat outside
!
interface Serial0
ip address 172.16.0.1 255.255.255.252
ip nat inside
!
router ospf 1
network 210.31.197.64 0.0.0.31 area 0.0.0.0
network 172.16.0.0 0.0.0.3 area 0.0.0.0
!
ip nat pool snc 210.31.197.93 210.31.197.93 netmask 255.255.255.224
ip nat inside source list 30 pool snc overload
ip nat inside source list 10 pool snc overload
ip classless
ip route 0.0.0.0 0.0.0.0 210.31.197.94
access-list 10 permit 172.16.0.0 0.0.255.255
access-list 30 permit 1.1.1.0 0.0.0.3
路由器C配置
C#sh run
ip subnet-zero
interface FastEthernet0
ip address 1.1.1.1 255.255.255.252
!
interface Serial0
ip address 172.16.0.2 255.255.255.252
clock rate 64000
!
router ospf 1
network 172.16.0.0 0.0.0.3 area 0.0.0.0
network 1.1.1.0 0.0.0.3 area 0.0.0.0
!
ip classless
!
5、路由表
B#sh ip route
1.0.0.0/30 is subnetted, 1 subnets
O 1.1.1.0 [110/49] via 172.16.0.2, 00:41:20, Serial0
210.31.197.0/27 is subnetted, 1 subnets
C 210.31.197.64 is directly connected, FastEthernet0
172.16.0.0/16 is variably subnetted, 6 subnets, 2 masks
C 172.16.0.0/30 is directly connected, Serial0
S* 0.0.0.0/0 is directly connected
C#sh ip route
1.0.0.0/30 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, FastEthernet0
210.31.197.0/27 is subnetted, 1 subnets
O 210.31.197.64 [110/49] via 172.16.0.1, 00:41:10, Serial0
172.16.0.0/16 is variably subnetted, 6 subnets, 2 masks
C 172.16.0.0/30 is directly connected, Serial0
6、問題：
B可以ping通A上的兩個端口的IP，而C只能ping通到A的F0，pc機也是如此，如何修改才能完成到A上F1口連通的配置？