BGP 实验R1能ping通R3，R3却不能ping通R1

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R1：
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface Ethernet0/0
ip address 172.16.1.1 255.255.255.0
half-duplex
!
interface Ethernet0/1
no ip address
shutdown
half-duplex
!
interface Ethernet0/2
no ip address
shutdown
half-duplex
!
interface Ethernet0/3
no ip address
shutdown
half-duplex
!
router bgp 1
bgp log-neighbor-changes
network 1.1.1.0 mask 255.255.255.0
neighbor 172.16.1.2 remote-as 2
!
ip classless
no ip http server
!
!



R2：
interface Loopback0
no ip address
!
interface Ethernet0/0
ip address 172.16.1.2 255.255.255.0
half-duplex
!
interface Ethernet0/1
ip address 10.1.1.1 255.255.255.252
half-duplex
!
interface Ethernet0/2
no ip address
shutdown
half-duplex
!
interface Ethernet0/3
no ip address
shutdown
half-duplex
!
router eigrp 1
network 10.0.0.0
network 172.16.0.0
no auto-summary
no eigrp log-neighbor-changes
!
router bgp 2
no synchronization
bgp log-neighbor-changes
neighbor 10.1.1.2 remote-as 2
neighbor 172.16.1.1 remote-as 1
!
ip classless
no ip http server
!



R3：

interface Loopback0
ip address 3.3.3.3 255.255.255.0
!
interface Ethernet0/0
no ip address
shutdown
half-duplex
!
interface Ethernet0/1
ip address 10.1.1.2 255.255.255.252
half-duplex
!
interface Ethernet0/2
no ip address
shutdown
half-duplex
!
interface Ethernet0/3
no ip address
shutdown
half-duplex
!
router eigrp 1
network 3.0.0.0
network 10.0.0.0
network 172.16.0.0
no auto-summary
no eigrp log-neighbor-changes
!
router bgp 2
bgp log-neighbor-changes
network 3.3.3.0 mask 255.255.255.0
neighbor 10.1.1.1 remote-as 2
!
ip classless
no ip http server
!

hongsupeng

R3想PING通R1的1.1.1.1要带源。R1PINGR3的3.3.3.3可以不用带源，因为有EIGRP的路由。

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R1#ping 3.3.3.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 36/64/92 ms
R1#trac
R1#traceroute 3.3.3.3

Type escape sequence to abort.
Tracing the route to 3.3.3.3

  1 172.16.1.2 12 msec 60 msec 32 msec
  2 10.1.1.2 72 msec 64 msec 64 msec
R1#ping 172.16.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 160/195/236 ms
R1#ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)






R3#ping 1.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
R3#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/40/68 ms
R3#ping 172.16.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 44/78/104 ms
R3#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)

leilei123056

太棒了，感谢楼主

梦じ如何演绎

问题在于 R3上在bgp 里面是有去往R1的 1.1.1.1的路由 但是IGP（eigrp ）里面没有去往1.1.1.1的路由。  你可以在R1上面起eigrp 把1.1.1.1 宣告进去 看看。

84983251

R3或者R2把接口的直连路由宣告进去

Rockyw

路过了解一下

On小-小ly

hongsupeng 发表于 2014-12-19 06:37
R3想PING通R1的1.1.1.1要带源。R1PINGR3的3.3.3.3可以不用带源，因为有EIGRP的路由。

答得最早~~最佳给你啦！谢谢！

初级网工

真正的问题在于R2指R3要带next-hop-self，2楼没有解决掉真正的问题

fengyuzhuifeng

我用你的实验重新做了一遍，结果发现问题出在，R1上没有10网段的路由，而R3ping到R1的时候，源IP地址用的是10.1.1.2，那么在R1找不到，所以回包回不去

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fengyuzhuifeng 发表于 2015-1-8 10:28
我用你的实验重新做了一遍，结果发现问题出在，R1上没有10网段的路由，而R3ping到R1的时候，源IP地址用的是 ...

是哎，让我更加理解了ping包，以前我一直以为ping都是知道怎么去，肯定知道怎么回来的