Route Authentication Example - Cisco Catalyst 4500 series Administration Manual

Configuring EIGRP Stub Routing
default route learned from the neighbors is displaced by the summary default route, or if the summary
route is the only default route present, all traffic destined for the default route does not leave the router.
Instead, this traffic is sent to the null 0 interface where it is dropped.
The recommended way to send only the default route out a given interface is to use a distribute-list
command. You can configure this command to filter all outbound route advertisements sent out the
interface with the exception of the default (0.0.0.0).

Route Authentication Example

The following example enables MD5 authentication on EIGRP packets in autonomous system 1:
Router A
interface ethernet 1
ip authentication mode eigrp 1 md5
ip authentication key-chain eigrp 1 holly
key chain holly
key 1
key-string 0987654321
accept-lifetime 04:00:00 Dec 4 1996 infinite
send-lifetime 04:00:00 Dec 4 1996 04:48:00 Dec 4 1996
exit
key 2
key-string 1234567890
accept-lifetime 04:00:00 Dec 4 1996 infinite
send-lifetime 04:45:00 Dec 4 1996 infinite
Router B
interface ethernet 1
ip authentication mode eigrp 1 md5
ip authentication key-chain eigrp 1 mikel
key chain mikel
key 1
key-string 0987654321
accept-lifetime 04:00:00 Dec 4 1996 infinite
send-lifetime 04:00:00 Dec 4 1996 infinite
exit
key 2
key-string 1234567890
accept-lifetime 04:00:00 Dec 4 1996 infinite
send-lifetime 04:45:00 Dec 4 1996 infinite
Router A accepts and attempts to verify the MD5 digest of any EIGRP packet with a key equal to 1. It
also accepts a packet with a key equal to 2. All other MD5 packets are dropped. Router A sends all
EIGRP packets with key 2.
Router B accepts key 1 or key 2, and sends key 1. In this scenario, MD5 authenticates.
Stub Routing Example
A router that is configured as a stub with the eigrp stub command shares connected and summary
routing information with all neighbor routers by default. Four optional keywords can be used with the
eigrp stub command to modify this operation:
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Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
34-20
receive-only
connected
Chapter 34 Configuring Layer 3 Interfaces
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