拓扑：

内部服务器配置：

interface FastEthernet0/0

ip address 192.168.1.1 255.255.255.0 duplex auto speed auto ! router ospf 100 router-id 1.1.1.1 log-adjacency-changes network 192.168.1.0 0.0.0.255 area 0

中心一配置：

crypto isakmp policy 10

authentication pre-share crypto isakmp key cisco address 0.0.0.0 0.0.0.0 crypto isakmp keepalive 10 periodic ! ! crypto ipsec transform-set trans esp-des esp-md5-hmac ! crypto ipsec profile dm***-profile set transform-set trans ! interface Tunnel2 bandwidth 1000 ip address 172.16.1.2 255.255.255.0 no ip redirects ip mtu 1400 ip nhrp map multicast dynamic ip nhrp map 172.16.1.3 10.1.1.3 ip nhrp map multicast 10.1.1.3 ip nhrp network-id 100 ip nhrp holdtime 3600 ip nhrp cache non-authoritative ip tcp adjust-mss 1360 ip ospf network broadcast ip ospf cost 100 ip ospf priority 2 delay 1000 tunnel source FastEthernet0/1 tunnel mode gre multipoint tunnel key 12345 tunnel protection ipsec profile dm***-profile ! interface FastEthernet0/0 ip address 192.168.1.2 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 ip address 10.1.1.2 255.255.255.0 duplex auto speed auto ! router ospf 100 router-id 2.2.2.2 log-adjacency-changes network 172.16.1.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 中心二配置：

crypto isakmp policy 10

authentication pre-share crypto isakmp key cisco address 0.0.0.0 0.0.0.0 crypto isakmp keepalive 10 periodic ! ! crypto ipsec transform-set trans esp-des esp-md5-hmac ! crypto ipsec profile dm***-profile set transform-set trans ! interface Tunnel3 bandwidth 1000 ip address 172.16.1.3 255.255.255.0 no ip redirects ip mtu 1400 ip nhrp map multicast dynamic ip nhrp map 172.16.1.2 10.1.1.2 ip nhrp map multicast 10.1.1.2 ip nhrp network-id 100 ip nhrp holdtime 3600 ip nhrp cache non-authoritative ip tcp adjust-mss 1360 ip ospf network broadcast ip ospf cost 105 ip ospf priority 2 delay 1000 tunnel source FastEthernet0/1 tunnel mode gre multipoint tunnel key 12345 tunnel protection ipsec profile dm***-profile ! interface FastEthernet0/0 ip address 192.168.1.3 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 ip address 10.1.1.3 255.255.255.0 duplex auto speed auto ! router ospf 100 router-id 3.3.3.3 log-adjacency-changes network 172.16.1.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0

分支一：

crypto isakmp policy 10

authentication pre-share crypto isakmp key cisco address 0.0.0.0 0.0.0.0 crypto isakmp keepalive 10 periodic ! ! crypto ipsec transform-set trans esp-des esp-md5-hmac ! crypto ipsec profile dm***-profile set transform-set trans ! interface Loopback0 ip address 4.4.4.4 255.255.255.0 ! interface Tunnel4 bandwidth 1000 ip address 172.16.1.4 255.255.255.0 no ip redirects ip mtu 1400 ip nhrp map 172.16.1.2 10.1.1.2 ip nhrp map multicast 10.1.1.2 ip nhrp map 172.16.1.3 10.1.1.3 ip nhrp map multicast 10.1.1.3 ip nhrp network-id 100 ip nhrp holdtime 3600 ip nhrp nhs 172.16.1.2 ip nhrp nhs 172.16.1.3 ip nhrp cache non-authoritative ip tcp adjust-mss 1360 ip ospf network broadcast ip ospf priority 0 delay 1000 tunnel source FastEthernet0/1 tunnel mode gre multipoint tunnel key 12345 tunnel protection ipsec profile dm***-profile ! interface FastEthernet0/1 ip address 10.1.1.4 255.255.255.0 duplex auto speed auto ! router ospf 100 router-id 4.4.4.4 log-adjacency-changes network 4.4.4.0 0.0.0.255 area 0 network 172.16.1.0 0.0.0.255 area 0

分支二配置：

crypto isakmp policy 10

authentication pre-share crypto isakmp key cisco address 0.0.0.0 0.0.0.0 crypto isakmp keepalive 10 periodic ! ! crypto ipsec transform-set trans esp-des esp-md5-hmac ! crypto ipsec profile dm***-profile set transform-set trans ! interface Loopback0 ip address 5.5.5.5 255.255.255.0 ! interface Tunnel5 bandwidth 1000 ip address 172.16.1.5 255.255.255.0 no ip redirects ip mtu 1400 ip nhrp map 172.16.1.2 10.1.1.2 ip nhrp map multicast 10.1.1.2 ip nhrp map 172.16.1.3 10.1.1.3 ip nhrp map multicast 10.1.1.3 ip nhrp network-id 100 ip nhrp holdtime 3600 ip nhrp nhs 172.16.1.2 ip nhrp nhs 172.16.1.3 ip nhrp cache non-authoritative ip tcp adjust-mss 1360 ip ospf network broadcast delay 1000 tunnel source FastEthernet0/1 tunnel mode gre multipoint tunnel key 12345 tunnel protection ipsec profile dm***-profile ! interface FastEthernet0/1 ip address 10.1.1.5 255.255.255.0 duplex auto speed auto ! router ospf 100 router-id 5.5.5.5 log-adjacency-changes network 5.5.5.0 0.0.0.255 area 0 network 172.16.1.0 0.0.0.255 area 0

验证：