【正文】
0 defaultinformation originate metric 999 metrictype 1!no ip serverip classlessip route ip route !accesslist 101 deny ip accesslist 101 permit ip anyaccesslist 102 permit ip anyno cdp runroutemap A permit 10 match ip address 101 set ip nexthop !routemap B permit 10 match ip address 102 set ip nexthop endconfig terminalip dhcp pool vlan21network defaultrouter dnsserver endR2enableconfig terminalhostname R2!bootstartmarkerbootendmarker!!no aaa newmodel!resource policy!memorysize iomem 5ip subnetzero!!ip cefno ip dhcp use vrf connected!!no ip domain lookupno ftpserver writeenable!interface FastEthernet0/0 ip address ip nat outside ip virtualreassembly duplex auto speed auto no shut!interface FastEthernet2/0 ip address ip nat inside ip virtualreassembly duplex auto speed auto no shut!interface FastEthernet3/0 ip address ip nat inside ip virtualreassembly duplex auto speed auto no shut!no ip serverip classlessip route ip route ip route 30!!ip nat inside source list 101 interface FastEthernet0/0 overload!accesslist 101 permit ip anyno cdp run!!controlplane!!line con 0 exectimeout 0 0 logging synchronousline aux 0 exectimeout 0 0 privilege level 15line vty 0 4 privilege level 15 no login!endS3enableconfig terminalip cefip dhcp relay information optionno ip dhcp use vrf connected! no ip domain lookupno ftpserver writeenable!spanningtree vlan 20 priority 0spanningtree vlan 21 priority 0spanningtree vlan 28 priority 0spanningtree vlan 300 priority 0spanningtree vlan 901 priority 0!interface FastEthernet1/0 switchport access vlan 901!interface FastEthernet1/1 switchport access vlan 28! interface FastEthernet1/2 switchport access vlan 20!interface FastEthernet1/3 switchport access vlan 21!interface FastEthernet1/4 spanningtree portfast!interface FastEthernet1/5 spanningtree portfast!interface FastEthernet1/6 spanningtree portfast!interface FastEthernet1/7 spanningtree portfast!interface FastEthernet1/8 spanningtree portfast!interface FastEthernet1/9 spanningtree portfast!interface FastEthernet1/10 spanningtree portfast!interface FastEthernet1/11spanningtree portfast!interface FastEthernet1/12spanningtree portfast!interface FastEthernet1/13spanningtree portfast!interface FastEthernet1/14spanningtree portfast!interface FastEthernet1/15!interface Vlan1 no ip address!interface Vlan20 ip address ip helperaddress !interface Vlan21 ip address ip helperaddress !interface Vlan28 ip address ip helperaddress !interface Vlan300 ip address !interface Vlan901 ip address !ip classlessip route endvlan databasevlan 20vlan 21vlan 28vlan 300vlan 901exitR4enableconfig terminalip cefip dhcp relay information optionno ip dhcp use vrf connected!no ip domain lookupno ftpserver writeenable!interface Loopback0 ip address !interface Serial0/0 bandwidth 2000 ip address serial restartdelay 0 no dceterminaltimingenable no shut!interface Serial0/1 bandwidth 2000 ip address serial restartdelay 0 no dceterminaltimingenable no shut!interface Serial0/2 no ip address shutdown serial restartdelay 0 no dceterminaltimingenable!interface Serial0/3 no ip address shutdown serial restartdelay 0 no dceterminaltimingenable!interface FastEthernet1/0 ip address ip helperaddress duplex auto speed auto no shut!interface FastEthernet2/0 ip address duplex auto speed auto no shut!router ospf 1 routerid logadjacencychanges network area 0 network area 0 network area 0 network area 0 network area 0R5enableconfig terminalip cefip dhcp relay information optionno ip dhcp use vrf connected!no ip domain lookupno ftpserver writeenable!interface Loopback0 ip address !interface Serial0/0 bandwidth 2000 ip address serial restartdelay 0 no dceterminaltimingenable no shut !interface Serial0/1 no ip address shutdown serial restartdelay 0 no dceterminaltimingenable!interface Serial0/2 no ip address shutdown serial restartdelay 0 no dceterminaltimingenable!interface Serial0/3 no ip address shutdown serial restartdelay 0 no dceterminaltimingenable!interface FastEthernet1/0 ip address ip helperaddress duplex auto speed auto no shut!interface FastEthernet2/0 ip address duplex auto speed auto no shut!router ospf 1 routerid logadjacencychanges network area 0 network area 0 network area 0 network area 040