EIGRP stub & queries

[John_S209]

I'm fortunate that I have folks presenting me with problems to work as I prep for CCNP Route exam.  this is another one of those, where I may think info is missing but am told "you have all you need."  re EIGRP stub networks/router & queries from neighbors - given this topology:

     R1--------------R2----------R3

      |                            |                     |

     Lo1:                       |                   Lo1:

23.23.23.23/32           |           11.11.11.11/32

                                 Lo1:

                         12.12.12.12/32

R3: eigrp stub

R2: Lo1# shut

so with R2 Lo1 shut, when R2 queries for a route to 12.12.12.12/32, of course R1 will receive this query.  but will R3 receive it, because it is an EIGRP stub router, and R2 should know this.  will R2 send a query to R3 anyway?

and also - R2 does not "know" this network because the loopback is shut?

thanks in advance.

[jalejand · Accepted solution]

R3 will not receive the query (R2 will queue it, but won't send it to R3) because R2 already knows about its stub router status from the neighbor information:

R2#show ip eigrp neighbors de
EIGRP-IPv4 Neighbors for AS(1)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
1 23.23.23.3 Gi2/0 10 00:01:13 17 102 0 29
Version 11.0/2.0, Retrans: 1, Retries: 0, Prefixes: 1
Topology-ids from peer - 0
Stub Peer Advertising (CONNECTED SUMMARY ) Routes -------------- neighbor is stub.

And yes, R2 will forget everything about that /32, it is no longer enabled, neither considered connected interface on its routing table

[Deepak Kumar · Accepted solution]

Hi,

R3 will not receive the query (R2 will queue it, but won't send it to R3). R2 will send an Update packet to R3 and R3 will withdraw the route for 12.12.12.12/32  from the routing table.