黑洞路由黑洞路由最好避开内部服务器映射的IP，否则在内部通过外部IP（通常由外部域名服务器给出）访问时会得不到结果，项目配置如上图所示。
(1)配置SwitchA
enable
conf t
vlan 10
exit
vlan 20
exit
vlan 30
exit
vlan 40
exit
ip routing
inter range f 0/1-5
switchport mode acc
switchport acc vlan 10
exit
inter range f 0/6-10
switchport mode acc
switchport acc vlan 20
exit
inter range f 0/11-15
switchport mode acc
switchport acc vlan 30
exit
inter f 0/24
switchport mode acc
switchport acc vlan 100
exit
inter vlan 10
ip add 192.168.1.1 255.255.255.0
no shut
exit
inter vlan 20
ip add 192.168.2.1 255.255.255.0
exit
inter vlan 30
ip add 192.168.3.1 255.255.255.0
exit
inter vlan 100
ip add 10.1.1.1 255.255.255.0
exit
router rip
ver 2
net 10.1.1.0
redis conn
exit
router rip
(2)配置RouterA
enable
conf t
inter f 0/0
ip add 10.1.1.2 255.255.255.0
ip nat inside
no shut
exit
inter f 0/1
ip add 202.1.1.1 255.255.255.0
ip nat outside
no shut
exit
ip route 0.0.0.0 0.0.0.0 202.1.1.2
router rip
ver 2
default ori
net 10.1.1.0
exit
ip nat in s stat 192.168.3.100 202.1.100.100 
(3)配置RouterB
enable
conf t
inter f 0/0
ip add 202.1.1.2 255.255.255.0
no shut
exit
ip route 202.1.100.0 255.255.255.0 202.1.1.1
ver 2
net 10.1.1.0