EIGRP || Advertise Loopback and Network simultaneously ||

[aantonis]

Hello everybody,

Assuming that you have 2 routers as EIGRP neighbors.
Router 1 is configured with a Loopback IP (192.168.1.1/32).

I would like to ask if there is a way to advertise on R2 two separate routes, one /32 and one /24.

 1. one route for 192.168.1.1/32

 2. one route for 192.168.1.0/24

Thanks

[Georg Pauwen]

Hello,

I am not clear on what you are asking: you want to advertise a summary route on R2 for an interface that is physically configured on R1 ?

Post the full configs of both routers and clarify what you want to achieve...

[aantonis]

Hello George,

Apologies the question was not clear enough. Let me re-phrase and correct a mistake as well.

We have 2 routers as EIGRP neighbors connected directed via the Gi0/0.

R1 is configured with a Loopback IP (192.168.1.1/24).

I would like to ask if there is a way to advertise to R2 two separate routes:

 1. one route for 192.168.1.0/24
 2. one route for 192.168.1.1/32

In other worlds, i would like to include the Loopback1 in the EIGRP route domain and the network as well.

Configuration as follows:

R1

!

int Lo1

 ip add 192.168.1.1 255.255.255.0

int Gi0/0

 ip add 172.28.12.1 255.255.255.0

!

router eigrp 12

 no auto

 passive-interface default
 no passive-interface Gi0/0
 net 172.28.12.0 0.0.0.255
 net 192.168.1.0 0.0.0.255

R2

!

int Gi0/0

 ip add 172.28.12.2 255.255.255.0

!

router eigrp 12

 no auto 

 passive-interface default
 no passive-interface Gi0/0
 net 172.28.12.0 0.0.0.255 

Thanks

[Georg Pauwen]

Hello,

thanks for the update, I'll have a look...

[Jon Marshall]

ip route 192.168.3.0 255.255.255.0 null0 

router eigrp 12
network 192.168.3.1 0.0.0.0
redistribute static

note if you have other downstream routers you may want the next hop to be an exit interface and if you have any other statics you may want to use a route map to filter which ones to redistribute. 

Jon

[Sergey Lisitsin · Accepted solution]

A.Androul,

If you re-configure your loopback IP address to be 192.168.1.1/32, then it will be very easy to achieve what you want:

conf t

ip access-list standard LOOP0

permit 192.168.1.1

route-map LEAK-LOOP0 permit 10

match ip address LOOP0

router eigrp 12

network 192.168.1.1 0.0.0.0

network 172.28.12.0 0.0.0.255

interface x/x

ip summary-address eigrp 12 192.168.1.0 255.255.255.0 leak-map LEAK-LOOP0

end

[aantonis]

Hi Sergey,

That works perfectly if Iconfigure the Loopback as /32 !!
Thanks for this :)

Any idea, how can we accomplish the same in case the Loopback is configured as /24 ?

Thanks

[Georg Pauwen]

Hello,

I have tried about everything possible and did not get it to advertise the host route (based on the original setup you had, with the loopback being a /24 route). You cannot summarize the 24 to a 32 (obviously I guess, since the /32 is not a summary).

[Sergey Lisitsin]

A.Androul,

I don't know what solution would work if you have a /24 configured on a loopback. But what is the requirement to have a /24 configured on it? It is only a loopback after all and doesn't really have access to a segment with 254 hosts on it. 

[Georg Pauwen]

Hello Sergey,

I tried this yesterday in GNS3 and didn't get it to work. Can you post the output of 'show ip route' on your R2 router, as I don't see the host route in mine ?

[aantonis]

Hi Georg,

In case the Loopback is configured as /32 , the solution provided by Sergey Lisitsin (summary-address & leak-map) is working perfect !!

In case the Loopback is configured as /24, then I do not know what is the trick to accomplish the same behavior.

[Georg Pauwen]

Hello,

honestly I don't think it is possible with the Loopback as a /24. You cannot summarize to /32, redistribution of static and connected doesn't work either, and there is no conditional route injection as in BGP...

[Sergey Lisitsin]

I agree,

I also can't think of a solution that would work. Furthermore, I don't see a need to configure it in that way if you can very easily achieve it with a /32 on a loopback.

[aantonis]

With Loopback configured as /32 , the solution provided by Sergey Lisitsin (summary-address & leak-map) is solid!

I will stick with this solution.

We can consider this discussion as solved !
Thanks much for your help.