RIP version are not compatible

[Mhammad139]

Subject : Rip V1, V2

Domain: issue (v2 and v1 are not compatible)

Level : all level

Dears i have two routers R1------- R2

R1 configuration used Rip V1

int fa 0/0

ip add 12.1.1.1 255.255.255.0

int lo 1

ip add 1.1.1.1 255.255.255.0 or 255.255.255.255

int lo 2

ip add 192.168.1.1 255.255.255.0 or 255.255.255.255

router rip

net 12.1.1.0

net 1.1.1.0

net 192.168.1.0

R2

int fa 0/0

ip add 12.1.1.2 255.255.255.0

int lo 1

ip add 2.2.2.2 255.255.255.0 or 255.255.255.255

int lo 2

ip add 95.1.1.1 255.255.255.0

router rip

ver 2

net 12.1.1.0

net 2.2.2.0

net 95.1.1.0

the issue is here from R1 I can ping to R2 loopback interfaces but form R2 I can't ping to R1 loopback interfaces.

so it means both versions are not compatible.

but when I change Rip version to version two in router 1

both devices can ping to the loopbacks in each device.

once I change rip version to version 1 there is still connection till i issue clear ip route *

so from this result mean there is no compatibility between both version

[paul driver]

Hello

Ripv 1
sends/receives rip updates via broadcast as default
Its classfull no matter if you disable auto- summerization which means ripv1 will not send routes with its subnet mask in its updates unless that route matches the classful subnet mask of its interface.

Ripv2  -   

sends/receives version 2 updates via multicast but can be configured to use broadcast and send/receive ripv1 updates. 
It is also classful by default but if you disable auto-summerization it becomes classless, meaning even though you can still can only apply classful network statements to the routing stanza, It will recognize and advertise the correct classless subnet.

So by default ripv1-ripv2 not compatible.but they can be configured to be so even when one rtr is running ripv1 and the other is running ripv2.

Lastly the reason why communication works when you changed one router from version2 back to version1 was the routes in the route table hadn't timed/flushed out but when you manually cleared the route table this caused communication to cease and routes that was learned to be removed.

[Mhammad139]

thanks dear actually I know How V1 and V2 are working cause captured all packets using Wireshark and Debug Command it shows me the mechanism of RIP updating.
I bought many courses on Networking most of the trainer mention that they are Compatible I just confused here cause by default not compatible