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New Member

EIGRP route summarization issue

Hi All,

I have question about EIGRP route summarization

Router 1 has following Loopback IPs

10.2.2.1

10.2.3.1

10.2.4.1

10.2.5.1

10.2.6.1

10.2.7.1

10.2.8.1

10.2.9.1

R1 is EIGRP nei to R2

To advertise the summary route I do this under R1 serial interface

Ip summart-address eigrp 100 10.2.0.0 255.255.248.0

As IP address in EIGRP the first IP always start with 0.0 that’s why I choose 10.2.0.0

Subnet mask I choose is 255.255.248.0 is this correct?

Now when I do s hip route on R2 it still shows following 2 IPs

10.2.8.0

10.2.9.0

So these two are not included under summary address any reason?

Thanks

Mahesh

  • LAN Switching and Routing
Everyone's tags (3)
3 ACCEPTED SOLUTIONS

Accepted Solutions
Silver

EIGRP route summarization issue

10.2.0.0 255.255.248.0 means 10.2.0.1 to 10.2.7.254--- this doesn't include 10.2.8.0 and 10.2.9.0.

to include 2.8 and 2.9, you have to choose a bigger mask 255.255.240.0 this will cover 10.2.0.1 to 10.2.15.254

Siddhartha

Re: EIGRP route summarization issue

Mahesh,

I show your summary address as:

10.2.2.0 255.255.240.0

10.2.0.0 255.255.240.0

HTH,

John

HTH, John *** Please rate all useful posts ***

Re: EIGRP route summarization issue

Hi John,

Your summary also includes networks 10,11,12,13,14 and 15.

therefore, Mahesh you would need to block, "10,11,12,13,14, and 15" and do not forget to deny network 0 and 1 as well via ACL if you want to.

thanks

Rizwan Rafeek

Message was edited by: Rizwan Mohamed

5 REPLIES
Silver

EIGRP route summarization issue

10.2.0.0 255.255.248.0 means 10.2.0.1 to 10.2.7.254--- this doesn't include 10.2.8.0 and 10.2.9.0.

to include 2.8 and 2.9, you have to choose a bigger mask 255.255.240.0 this will cover 10.2.0.1 to 10.2.15.254

Siddhartha

Re: EIGRP route summarization issue

Mahesh,

I show your summary address as:

10.2.2.0 255.255.240.0

10.2.0.0 255.255.240.0

HTH,

John

HTH, John *** Please rate all useful posts ***

Re: EIGRP route summarization issue

Hi John,

Your summary also includes networks 10,11,12,13,14 and 15.

therefore, Mahesh you would need to block, "10,11,12,13,14, and 15" and do not forget to deny network 0 and 1 as well via ACL if you want to.

thanks

Rizwan Rafeek

Message was edited by: Rizwan Mohamed

New Member

EIGRP route summarization issue

Hi all,

It is working fine now

i used summary address 10.2.0.0 255.25.240.

Thanks everyone for their help

Thanks

MAhesh

New Member

EIGRP route summarization issue


Hi John,

Yes the subnet mask is 255.255.240.0  i got this by doing binary method

Will try this in my  config and will let you know

Thanks

Mahesh

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