Solved

BGP Network Advertising

Posted on 2014-04-02
3
358 Views
Last Modified: 2016-11-23
I have network behind core switch is 192.168.10.0/25
and my routing to corporate network is BGP routing. I published my network at BGP as 192.168.10.0/24 because we have other subnet that also using 192.168.10.241/28 that doing routing internally.

at Corp router, they only allowed our subnet advertise as /24.
all my server which is using /25 subnet is not able to reach the next hop at Corp. which according to them they can't find my subnet advertised at their route table.
if to ask them change to accept my subnet which is /25 required a lot of process and paper work and question that to answer to justify it. the flow may take longer.

i understand that auto summarization may help... but i seem can't find the command in my switch.

By the way, I'm using Dell Force10 S4810. all this works perfectly until the host subnet been requested to change to /25

tks
0
Comment
Question by:hell_angel
3 Comments
 
LVL 17

Accepted Solution

by:
pergr earned 500 total points
ID: 39974135
Most likely the issue is that in order to advertise a /24 route in BGP, you first must have that /24 route in your routing table.

You typically do that by setting a static route for the /24, with next-hop as "null0" or "discard", or what ever the vendor software will call it.

Once that is done, the /24 will be advertised and the Corp should see it.
0
 

Author Comment

by:hell_angel
ID: 39974234
it solved.

added ip route to null and aggregate -address
0
 
LVL 28

Expert Comment

by:mikebernhardt
ID: 39975745
For your router to advertise the BGP route of 192.168.10.0/24, you need to have that route in your internal routing table already. What you want to do is correct though.

The solution is to put a static route in your BGP router:
ip route 192.168.10.0 255.255.255.0 null0

This will allow your router to advertise that route in BGP. Because routers always route to the most specific route, your existing routes will continue to work. Any traffic sent to a /24 destination that doesn't actually exist will simply be dropped.
0

Featured Post

Microsoft Certification Exam 74-409

Veeam® is happy to provide the Microsoft community with a study guide prepared by MVP and MCT, Orin Thomas. This guide will take you through each of the exam objectives, helping you to prepare for and pass the examination.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

BIND is the most widely used Name Server. A Name Server is the one that translates a site name to it's IP address. There is a new bug in BIND (https://kb.isc.org/article/AA-01272), affecting all versions of BIND 9 from BIND 9.1.0 (inclusive) thro…
The use of stolen credentials is a hot commodity this year allowing threat actors to move laterally within the network in order to avoid breach detection.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

919 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now