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eBGP and iBGP issue

Hey guys,

I have a problem with this topology, I'm new to BGP so I'm trying to understand this.

(R1)

ip route 192.168.2.2 255.255.255.255 209.165.202.130

router bgp 65100
bgp log-neighbor-changes
network 209.165.200.224 mask 255.255.255.224
neighbor 192.168.2.2 remote-as 65000
neighbor 192.168.2.2 ebgp-multihop 255
neighbor 192.168.2.2 update-source Loopback0

(R2)

ip route 209.165.201.1 255.255.255.255 209.165.202.129

router bgp 65000
bgp log-neighbor-changes
network 192.168.22.0
neighbor 192.168.3.3 remote-as 65000
neighbor 192.168.3.3 update-source Loopback0
neighbor 192.168.3.3 next-hop-self
neighbor 209.165.201.1 remote-as 65100
neighbor 209.165.201.1 ebgp-multihop 255
neighbor 209.165.201.1 update-source Loopback0

(R3)

router bgp 65000
bgp log-neighbor-changes
network 192.168.33.0
neighbor 192.168.2.2 remote-as 65000
neighbor 192.168.2.2 update-source Loopback0

The thing I dont understand is that R1 and R2 can ping each other but R1 and R3 can't
Both R1 and R3 have entrees in the bgp table for each other but wont ping each other.

Can someone explain why?

1 Accepted Solution

Accepted Solutions

Deepak Kumar
VIP Alumni
VIP Alumni

Hello Ariya,

I am checking you are missing some configuration as below

R2:

ip route 192.168.3.3 255.255.255.255 172.16.23.3

R3:

ip route 192.168.2.2 255.255.255.255 172.16.23.2

Why you are using the static route for your wan link. You should use the default route for WAN link on R2 router.

Don't worry, If you want to keep the same configuration as you did then use Source Loopback interface 1 during the ping command:

Example:

R1#ping 192.168.33.1 source loopback 1

Regards,

Deepak Kumar

www.deepuverma.in 

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

View solution in original post

10 Replies 10

Pawan Raut
Level 4
Level 4

Because you don't have route for R1 in R3 routing table similarly  no route for R3 in R1 routing table

I did have routes for both, I did traceroute and it looks like it drops it at R2

Deepak Kumar
VIP Alumni
VIP Alumni

Hello Ariya,

I am checking you are missing some configuration as below

R2:

ip route 192.168.3.3 255.255.255.255 172.16.23.3

R3:

ip route 192.168.2.2 255.255.255.255 172.16.23.2

Why you are using the static route for your wan link. You should use the default route for WAN link on R2 router.

Don't worry, If you want to keep the same configuration as you did then use Source Loopback interface 1 during the ping command:

Example:

R1#ping 192.168.33.1 source loopback 1

Regards,

Deepak Kumar

www.deepuverma.in 

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

Hello Deepak,

I'm running OSPF on R2 and R3 so no need for static routes.

R1#ping 192.168.33.1 source loopback 1 ... did actually work.

Can you explain why it doesnt work as ping 192.168.33.1 but when you use source loopback, it will actually ping, I guess that made me confused 

Hi Deepak,

redistribute bgp into ospf on R2 that should fix the problem.

Dear Gaurav,

As I can understand, He is using OSPF or Static routing to communicate loopback interface with each other and BGP is another think.

Regards,

Deepak Kumar

www.deepuverma.in

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

Thanks for mark my answer as correct.

But you didn't mention in the question about OSPF configuration. 

Regards,

Deepak Kumar

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

Yea sorry about that. 

So can you explain why it doesn't work if you don't use "source loopback" when pinging?

HI Ariya,

When you trying to ping without "Source Loopback" then ICMP packet come with "Source IP 209.165.202.129"  but R3 does not have any information about IP 209.165.202.129 in its routing table so packet dropped when R3 will trying to make reply. 

Regards,

Deepak Kumar

www.deepuverma.in

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution if this comment will help you!

Ohh yea makes sense now.

Thanks a lot. 

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