RIPv1 vs RIPv2

LAN1---R1---FR---R2---LAN2

LAN1 = 10.1.0.0/16
FRAME = 12.0.0.0/8
LAN2 = 10.2.0.0/16

RIP on all interfaces.

When version 1 is in use, here are the route tables:

R1:

R1#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/16 is subnetted, 1 subnets
C 10.1.0.0 is directly connected, FastEthernet0/0
C 12.0.0.0/8 is directly connected, Serial1/0
R1#

R2:

R2#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/16 is subnetted, 1 subnets
C 10.2.0.0 is directly connected, FastEthernet0/0
C 12.0.0.0/8 is directly connected, Serial1/0
R2#

Now Let's enable RIP version 2, but with auto-summary:

R1(config)#router rip
R1(config-router)#ve 2

R2(config)#router rip
R2(config-router)#v 2

Another look at the route tables.

R1#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
R 10.0.0.0/8 [120/1] via 12.0.0.2, 00:00:07, Serial1/0
C 10.1.0.0/16 is directly connected, FastEthernet0/0
C 12.0.0.0/8 is directly connected, Serial1/0
R1#

R2#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.2.0.0/16 is directly connected, FastEthernet0/0
R 10.0.0.0/8 [120/1] via 12.0.0.1, 00:00:17, Serial1/0
C 12.0.0.0/8 is directly connected, Serial1/0
R2#

Notice that the 10.0.0.0/8 network shows up on both routers! Watch out for the loop:

R1#trace 10.3.3.3

Type escape sequence to abort.
Tracing the route to 10.3.3.3

1 12.0.0.2 72 msec 16 msec 8 msec
2 * * *
3 * * *
4 * * *
5 * * *
6 *

I think this packet is looping, R1 can't really send a time-exceeded message to itself so we see the "*". If I am wrong, please correct me.

Let's disable auto-summary now and then check the tables again:

R1(config)#router rip
R1(config-router)#no auto-summary
R1#clear ip route *

R2(config)#router rip
R2(config-router)#no auto-summary
R2#clear ip route *

R1#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/16 is subnetted, 2 subnets
R 10.2.0.0 [120/1] via 12.0.0.2, 00:00:01, Serial1/0
C 10.1.0.0 is directly connected, FastEthernet0/0
C 12.0.0.0/8 is directly connected, Serial1/0
R1#

R2#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/16 is subnetted, 2 subnets
C 10.2.0.0 is directly connected, FastEthernet0/0
R 10.1.0.0 [120/1] via 12.0.0.1, 00:00:14, Serial1/0
C 12.0.0.0/8 is directly connected, Serial1/0
R2#

That's looks right now but rraceroute doesn't get much better:

R1#trace 10.3.3.3

Type escape sequence to abort.
Tracing the route to 10.3.3.3

1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
6 * *

Not really sure why traceroute doesn't die...got any ideas?