发现GNS3的bug

小虎

在学习ccnp之前想通做ccna所有的实验！就在刚上手时就遇到问题了！废话不多说！直接进入主题：


做最简单的静态浮动路由，通过e口做默认的静态路由，通过s口做管理距离为100的静态路由，然后查看路由表：结果默认管理距离的路由被添加到路由表，完全正确，接下来问题出现了！
        我down掉其中一台路由器的e口，在其查看路由表，果然管理距离为100的浮动路由被加进来了，但是另一台路由器路由表却保持不变，还是管理距离为1的路由条目：
     R1的配置：
     !
interface Loopback0
ip address 172.16.1.1 255.255.255.0
!
interface Ethernet0/0
ip address 172.16.21.1 255.255.255.0
shutdown
interface Serial1/0
ip address 172.16.12.1 255.255.255.0
serial restart-delay 0
no ip http server
ip route 172.16.2.0 255.255.255.0 172.16.21.2
ip route 172.16.2.0 255.255.255.0 172.16.12.2 100


    R2的配置：
interface Loopback0
ip address 172.16.2.2 255.255.255.0
!
interface Ethernet0/0
ip address 172.16.21.2 255.255.255.0
half-duplex
interface Serial1/0
ip address 172.16.12.2 255.255.255.0
serial restart-delay 0
!
no ip http server
ip route 172.16.1.0 255.255.255.0 172.16.21.1
ip route 172.16.1.0 255.255.255.0 172.16.12.1 100

down掉R1的e口之前的路由表：

R1：
R1#show ip rout
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
     172.16.0.0/24 is subnetted, 4 subnets
C       172.16.21.0 is directly connected, Ethernet0/0
C       172.16.12.0 is directly connected, Serial1/0
C       172.16.1.0 is directly connected, Loopback0
S       172.16.2.0 [1/0] via 172.16.21.2

R2：
R2#show ip rout
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
     172.16.0.0/24 is subnetted, 4 subnets
C       172.16.21.0 is directly connected, Ethernet0/0
C       172.16.12.0 is directly connected, Serial1/0
S       172.16.1.0 [1/0] via 172.16.21.1
C       172.16.2.0 is directly connected, Loopback0


down掉之前路由表完全正确，下面down掉R1的e口：路由表如下
R1：
R1#
R1#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#int e0/0
R1(config-if)#shut
R1(config-if)#end
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
     172.16.0.0/24 is subnetted, 3 subnets
C       172.16.12.0 is directly connected, Serial1/0
C       172.16.1.0 is directly connected, Loopback0
S       172.16.2.0 [100/0] via 172.16.12.2
R1的路由表添加了管理距离为100的浮动路由，下面看R2的路由表
R2：
R2#show ip rout
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
     172.16.0.0/24 is subnetted, 4 subnets
C       172.16.21.0 is directly connected, Ethernet0/0
C       172.16.12.0 is directly connected, Serial1/0
S       172.16.1.0 [1/0] via 172.16.21.1
C       172.16.2.0 is directly connected, Loopback0
R2的路由表却没有变

下面我们从R2ping172.16.1.1
R2#show ip rout
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
     172.16.0.0/24 is subnetted, 4 subnets
C       172.16.21.0 is directly connected, Ethernet0/0
C       172.16.12.0 is directly connected, Serial1/0
S       172.16.1.0 [1/0] via 172.16.21.1
C       172.16.2.0 is directly connected, Loopback0
R2#ping 172.16.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)



大家看明白了吧？这个问题不懂是什么问题，配置应该没问题，但是问题却出现了，大家各抒己见！目的是解决问题

布凡

承认我错了  
谢谢LINDA MAGIC    不过用都用串口做的话事可以的    用FASTE的话会发生问题 试想中间加个交换机么
gns3 无法检测对端端口关闭 CDP 虽然能检测到对方挂了但是无法清除
。。LZ 好样的
R1#debug ip routing
IP routing debugging is on
R1#
*Mar  1 00:21:16.207: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
R1#
*Mar  1 00:21:16.211: is_up: 0 state: 4 sub state: 1 line: 0 has_route: True
*Mar  1 00:21:16.215: RT: interface Serial0/0 removed from routing table
*Mar  1 00:21:16.215: RT: del 1.1.1.0/24 via 0.0.0.0, connected metric [0/0]
*Mar  1 00:21:16.215: RT: delete subnet route to 1.1.1.0/24
*Mar  1 00:21:16.219: RT: NET-RED 1.1.1.0/24
*Mar  1 00:21:16.219: RT: delete network route to 1.0.0.0
*Mar  1 00:21:16.219: RT: NET-RED 1.0.0.0/8
R1#
*Mar  1 00:21:17.219: RT: del 192.168.2.0 via 1.1.1.2, static metric [1/0]
*Mar  1 00:21:17.219: RT: delete network route to 192.168.2.0
*Mar  1 00:21:17.219: RT: NET-RED 192.168.2.0/24
*Mar  1 00:21:17.223: RT: SET_LAST_RDB for 192.168.2.0/24
  NEW rdb: via 2.2.2.2
*Mar  1 00:21:17.223: RT: add 192.168.2.0/24 via 2.2.2.2, static metric [100/0]
*Mar  1 00:21:17.227: RT: NET-RED 192.168.2.0/24

magic_os

这个是个好问题~
配置完全正确~

按照你这个配置在Cisco Packet Tracer模拟器上是可以成功实现浮动静态路由的..
GNS或者说dynamips上面都出现了这个问题~即关闭任意一边的e口都不会影响对端的静态路由配置..在dynamips或者GNS中只要本地的这个接口no shutdown那么这条静态路由就会生效并且按照路由选路的原则最小管理距离会进入路由表
这个应该是和模拟器有关系的..
在真实环境中应该和Packet Tracer模拟器的试验结果是一样的~


关于GNS的接口加电的问题我以前也遇到过..就是那个16口的交换模块必须是在启动前先连接线缆,接口才会双up，启动后你再在GNS中用交换机或者路由器去连接到这个交换模块上的任意接口，接口都是up down的..

不知道其他人有没有不同观点~欢迎跟帖讨论~

亮晶晶

linda.!

LZ使用GNS3是会出现这样的问题的，你把其中E0口shutdown了，在模拟环境中对方是检测不到的，所以对方的浮动静态路由不会添加进路由表中，建议将对方的E0口也shutdown！
但是在真实环境中可以检测到，不会出现这样的问题！

明天¤晴天℃

大家都好厉害啊

布凡

回复 5 # linda.! 的帖子

我错了
一直模拟器没深究 学习

WangyyITer

学习了