BGP Prevent Transit AS

Lessons Discussion
1

This topic is to discuss the following lesson:

3

Many thanks for the lesson, it’s very easy to understand!

4

What about this method, Rene?

access-list 1 permit 1.1.1.0 0.0.0.255

route-map NO-EXPORT permit 10
  match ip address 1

neighbor 192.168.12.2 route-map NO-EXPORT out
neighbor 192.168.13.3 route-map NO-EXPORT out

Ofc we can use “match ip address prefix-list” as well. And my deepest respect for all what you do for us all.

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5

An access-list will work as well, no problem at all :slight_smile:

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6

Nice!!! It cleared my questions!!! Thanks a ton!!!

7

You are welcome Ulhas.

8

Hello Rene,

I have gone through many topics in this website and that cleared my idea as well but I don’t see any note regarding Multiple Spanning-Tree Protocol.
If you share some labs/note for MSTP will be helpful for me to understand it better.

Thanks a lot.

9

Thanks a million Rene!! I really appreciate you sharing your knowledge, this really helped me out a lot.

10

You are welcome Marcus!

11

Hello Arijit,

I’m glad to hear that you like it. I’ll add some MST material in the future!

Rene

12

You have really cleared the air on some difficulties i was having.
Really self explanatory.
Thx Renee

13

This really helped me :slight_smile:
Thanks a lot Rene

14

Nice and neat, i like it :slight_smile:

15

Rene,

Nice and clear explanation of all the complex BGP terms.
Great lesson to understand key features of BGP.

Thanks
Hamood

16

Thanks Hamood

17

Hi,

I would appreciate if you can talk about how to advertise routes toward inside your network.

let say you have r1 and r2 are mutihome. R1 to isp1 and R2 to isp2 (getting bgp full table). Now let say you have R1 and R2 criss cross connected to nexus 7k inbound. I know you can run iBGP but that would be too many routes to your switches. What would be a good solution in this situation?

Thanks,
Nav

18

Hi Nav,

If R1 and R2 are the only exit points for your network then a default route will do the job, no need to run iBGP on all your internal devices.

Rene

19

Hello Rene,

Great job as always, it is possible if you publish the routers configurations? I would like to see how you did the configuration, this also helps me clearing the theory.

It’s just a question.

Thank you very much!!

20

Hi Diana,

Do you mean the startup configurations?

In the most recent lessons I have been adding the final configurations, for example:

MPLS Layer 3 VPN PE CE OSPF

Rene

21

Rene – in your example of Filter-list with AS PATH access-list you wrote:

R1(config)#ip as-path access-list 1 permit ^$

Is the AS number of R1 suppose to go between the ^ and the $? In your example you didn’t specify an AS # - let’s just say R1 AS # is 4444. Should it look like this?

R1(config)#ip as-path access-list 1 permit ^4444$

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