Cisco CCNP and CCIE Study Notes

Consider two routers connected back-to-back via their ethernet interfaces. The configs on the two routers is as follows

Router1

interface Ethernet0
 ip address 10.0.0.1 255.255.255.0
!
ip route 20.0.0.0 255.255.255.0 10.0.0.2
ip route 30.0.0.0 255.255.255.0 10.0.0.2

Router2

interface Loopback0
 ip address 20.0.0.1 255.255.255.255
 no clns route-cache
!
interface Loopback1
 ip address 30.0.0.1 255.255.255.255
 no clns route-cache
!
interface Ethernet0
 ip address 10.0.0.2 255.255.255.0
 no clns route-cache

Now, assume that a ping is initiated from Router1 to 20.0.0.1 and 30.0.0.1. The pings succeed and "show arp" on Router1 shows

Router1#show arp
Protocol  Address      Age (min)  Hardware Addr   Type   Interface
Internet  10.0.0.2           18   0000.cc00.8400  ARPA   Ethernet0
Internet  10.0.0.1            -   0000.cc00.8300  ARPA   Ethernet0

Your task in this problem is to come up with two different ways in which the config of Router1 can be modified such that if you ping 20.0.0.1 and 30.0.0.1 from Router1, "show arp" on Router1 will show up as

Router1#sh arp
Protocol  Address      Age (min)  Hardware Addr   Type   Interface
Internet  10.0.0.2            0   0000.cc00.8400  ARPA   Ethernet0
Internet  10.0.0.1            -   0000.cc00.8300  ARPA   Ethernet0
Internet  20.0.0.1            0   0000.cc00.8400  ARPA   Ethernet0
Internet  30.0.0.1            1   0000.cc00.8400  ARPA   Ethernet0