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JANOG50 NETCON 問題1-1解説
問題文
インターネットインフラに興味を持ったAさんは、まずルーター機器のルーティングについて勉強し始めました。
Aさんは以下の物理構成となるネットワークを構築し、２台のPCの間に３台のルーターを通してpingを送ろうとしました。
しかし、なぜかpingが対向のPCに届きません。
VPC1からVPC2へpingが送れるようにしてください。
解決条件: VPC1にて「ping 192.168.11.200 」を実行し、疎通できること。
トポロジー図
VM上のNW構成図
コンフィグ概要
問題初期config
Config_vIOS1
Config_vIOS1
!
version 15.9
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname vIOS1
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
!
!
!
!
!
!
!
!
!
!
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
redundancy
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface GigabitEthernet0/0
no shutdown
ip address 192.168.0.254 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/1
no shutdown
ip address 192.168.10.254 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/2
no shutdown
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/3
no shutdown
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
ip route 192.168.11.0 255.255.255.0 192.168.0.253
!
ipv6 ioam timestamp
!
!
!
control-plane
!
banner exec ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
banner incoming ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
banner login ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
!
line con 0
line aux 0
line vty 0 4
login
transport input none
!
no scheduler allocate
!
end
Config_vIOS2
Config_vIOS2
!
version 15.9
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname vIOS2
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
!
!
!
!
!
!
!
!
!
!
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
redundancy
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface GigabitEthernet0/0
no shutdown
ip address 192.168.0.253 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/1
no shutdown
ip address 192.168.1.253 255.255.255.0
shutdown
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/2
no shutdown
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/3
no shutdown
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
ip route 192.168.10.0 255.255.255.0 192.168.0.254
ip route 192.168.11.0 255.255.255.0 192.168.1.252
!
ipv6 ioam timestamp
!
!
!
control-plane
!
banner exec ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
banner incoming ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
banner login ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
!
line con 0
line aux 0
line vty 0 4
login
transport input none
!
no scheduler allocate
!
end
Config_vIOS3
Config_vIOS3
!
version 15.9
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname vIOS3
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
!
!
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
!
!
!
!
!
!
!
!
!
!
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
redundancy
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
interface GigabitEthernet0/0
no shutdown
ip address 192.168.1.252 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/1
no shutdown
ip address 192.168.11.252 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/2
no shutdown
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/3
no shutdown
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
ip forward-protocol nd
!
!
no ip http server
no ip http secure-server
ip route 192.168.10.0 255.255.255.0 192.168.1.253
!
ipv6 ioam timestamp
!
!
!
control-plane
!
banner exec ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
banner incoming ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
banner login ^C
**************************************************************************
* IOSv is strictly limited to use for evaluation, demonstration and IOS *
* education. IOSv is provided as-is and is not supported by Cisco's *
* Technical Advisory Center. Any use or disclosure, in whole or in part, *
* of the IOSv Software or Documentation to any third party for any *
* purposes is expressly prohibited except as otherwise authorized by *
* Cisco in writing. *
**************************************************************************^C
!
line con 0
line aux 0
line vty 0 4
login
transport input none
!
no scheduler allocate
!
end
-Config_VPC1
Config_VPC1
ip 192.168.10.100 192.168.10.254 24
-Config_VPC2
Config_VPC2
ip 192.168.11.200 192.168.11.252 24
制限事項/注意事項
VPCからquitで出るとVM側で電源を落としてしまい、採点ができなくなるので注意。
telnet経由でログインしているため、"Ctrl + ]"からtelnetのコンソールに入り、"q"でtelnet接続を切れます。
もし落としてしまった場合はNETCON委員が対応します。
問題解説
まず、PC、及び各ルータ内の状態を確認するためにpingを用います。
VPC1の対向から順番に実施していくと、vIOS2のgi0/0までは疎通できました。
どうやら此処でpingが途絶えているようです。
vIOS2のインターフェース情報を確認すると、以下の結果が得られました。
show ip interface brief
vIOS2#show ip int brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 192.168.0.253 YES NVRAM up up
GigabitEthernet0/1 192.168.1.253 YES NVRAM administratively down down
GigabitEthernet0/2 unassigned YES NVRAM administratively down down
GigabitEthernet0/3 unassigned YES NVRAM administratively down down
showコマンドの結果から、vIOS2のGi0/1がshutdown状態になっていることが分かります。
どうやらこの部分が原因のようです。
このshutdown状態をup状態に変更します。
以下のようにConfig投入します。
回答例
vIOS2#conf t
vIOS(config)#int gi 0/1
vIOS(config-if)#no shutdown
vIOS(config-if)#end
vIOS2の設定変更が完了したので、vIOS3やVPC2が正常に通るかpingコマンドで確認します。
下記は解決条件であるVPC1からVPC2へのpingを用いた確認の結果になります。
確認コマンド
VPCS> ping 192.168.11.200
84 bytes from 192.168.11.200 icmp_seq=1 ttl=61 time=5.499 ms
84 bytes from 192.168.11.200 icmp_seq=2 ttl=61 time=4.473 ms
84 bytes from 192.168.11.200 icmp_seq=3 ttl=61 time=10.497 ms
84 bytes from 192.168.11.200 icmp_seq=4 ttl=61 time=3.187 ms
84 bytes from 192.168.11.200 icmp_seq=5 ttl=61 time=7.450 ms
問題なくpingが通っているため、問題解決となります。
Discussion