EIGRP redistribute static

[sebastien3]

Hello,

I have two routers directly connected. I want to use eigrp to redistribute the static routes present on R2 to R1.

On R2 (192.168.1.2/30) I have a default route that points to R1 (192.168.1.1/30) :
ip route 0.0.0.0 0.0.0.0 192168.1.1

On R1 I also receive 0.0.0.0, this can be a problem...

P 0.0.0.0/0, 0 successors, FD is Infinity
via 192.168.1.1 (3072/2816), GigabitEthernet0/1/4

How to remove 0.0.0.0 and let the rest of the static routes pass ?

Thnaks !

[sebastien3]

Hi @David Ruess 

Thank you, I'm in option 2 ! This currently option 2 which I use with an access-list to filter the default route.

distribute-list 1 out GigabitEthernet0/1/4
redistribute connected
redistribute static
exit-af-topology
network 192.168.1.0 0.0.0.3
eigrp router-id 192.168.1.1
eigrp stub redistributed

access-list 1 deny 0.0.0.0
access-list 1 permit any

[David Ruess]

Hello,

I think I missed a part in the initial post. I see you are trying to use redistribution of static connected routes in EIGRP. There is a simpler way to achieve the same result below.

If R1 has a default 0.0.0.0/0 route why don't you just advertise that to R2 (there are several ways to do this). That way you can get rid of the static default route in R2 and alleviate the problem of advertising the default back to R1. Then on R2 you can use the redistribute static/connected command to solve your issue.

If this doesn't help as you see there are a couple solutions to your issue by other posters. Also if this doesnt help can you provide the full config of the devices so we can see how everythin is set up/advertised?

-David

[Giuseppe Larosa]

Hello @sebastien3 ,

>>

On R1 I also receive 0.0.0.0, this can be a problem...

P 0.0.0.0/0, 0 successors, FD is Infinity
via 192.168.1.1 (3072/2816), GigabitEthernet0/1/4

Actually it is not a problem as you see on R1 number of successor is 0 and FD is infinity this means that R1 is not going to use this EIGRP route.

However, I can agree that it would a cleaner design to filter the  prefix 0.0.0.0/0 out of R2 in the ways discussed in the thread.

Here we see how EIGRP is able to protect itself from a route that has an IP next-hop equal to a local IP address on R1.

Hope to help

Giuseppe

[sebastien3]

Hi @Giuseppe Larosa 

Yes as indicated it is better not to have this route and to filter it. Even if EIGRP indicates 0.0.0.0 in Infinity 0 successors if one day there is a configuration problem on the EIGRP network it should not propagate this route to the other neighbors...

[sebastien3]

Hi all !

Here is a diagram to understand the expected operation.

Core 1 + Core 2 are connected in BGP to ISPs (IP transit)
Core 1 + Core 2 + RA + RB + R1 forms an EIGRP topology to exchange the different networks.
Core 1 + Core 2 + RA + RB + R1 also uses BGP : Core 1 + Core 2 send default route 0.0.0.0 to RA + RB + R1, nothing else.
RA + RB + R1 announces via EIGRP the networks that are directly connected to them.
R2 : EIGRP STUB ?
=> R2 announces the networks that are directly connected to it in order to propagate it to the other network participants via R1.

[MHM Cisco World]

....

[sebastien3]

R2 is used to terminate L2TP sessions. Is it now OK for you ?

[paul driver]

Hello

---

@sebastien3 wrote:

I have two routers directly connected. I want to use eigrp to redistribute the static routes present on R2 to R1.
How to remove 0.0.0.0 and let the rest of the static routes pass ?

---

Why not append a tag to the static routes you wish to advertise?

ip route x.x.x.x x.x.x.x y,y,y,y,. tag 1
ip route x.x.x.x x.x.x.a y,y,y,y,. tag 1
ip route x.x.x.x x.x.x.b y,y,y.y,. tag 1
ip route x.x.x.x x.x.x.c y,y,y,y,. tag 1

route-map static-routes
match tag 1
router eigrp xx
redistribute static route-map static-routes

[sebastien3]

Hi @paul driver 

Yes this is a good idea for static routes but not for directly connected routes (IP returned by RADIUS).

[paul driver]

Hello

what about the connected routes - whats that have to do with redistributiing tagged static routes?
Your OP is querying how to redistribute specific static routes correct?
you can redistribute specific connected routes with a route-map is you desire but usually you do this via a network statement under the routing process.

[MHM Cisco World]

...

[sebastien3]

Hi @MHM Cisco World 

Thank you for this note Core1-Core2 link down ! On my drawing we see that Core1 and Core2 are connected to each other BUT they are also connected to each other via a second path (switch).

If the Core1-Core2 connection fails, normally it falls back to the switch so there is no cut...

In this case and design should I configure R1 in EIGRP STUB ?

[David Ruess]

If you configure any router on your network as a STUB its should be the last router in the topology in any location (i.e. no other router behind it). You CAN configure a non-edge router as a STUB but you would have to do some workarounds with summary-addresses and leak-maps making it a bit more complicated.

You are correct that R1 will not become a transit router if the link goes down.

[sebastien3]

---

@David Ruess wrote:

If you configure any router on your network as a STUB its should be the last router in the topology in any location (i.e. no other router behind it). You CAN configure a non-edge router as a STUB but you would have to do some workarounds with summary-addresses and leak-maps making it a bit more complicated.

---

Here it is indeed the case of R2, there are no other routers behind that is why the STUB mode seemed ideal to me.

Can you explain "some workarounds" to me ?

[David Ruess]

@MHM Cisco World mentioned these workarounds in a previous post. I couldn’t figure out how to copy on my phone but it was this one.