Redistributing connected secondary ip

[bijay.swain]

Hi All

Below is the config of a device running RIP

interface Vlan10
ip address 10.4.4.40 255.0.0.0
!
interface Vlan4
ip address 192.183.12.1 255.255.254.0 secondary
ip address 192.183.74.1 255.255.255.0

router rip
redistribute connected
network 10.0.0.0

My Question is this device is advertising the

192.183.74.0

network via RIP but why it is not advertising the

192.183.12.0

network .

[bijay.swain]

Hi 

RIP version 2 did solved .now it is advertising the

192.183.12.0/23

network through rip but another question comes as why it was not able to advertise

192.183.12.0 using /24

mask which is class C default .

[David Ruess]

Hello,

RIPv1 being a very old protocol likely didn't support that feature. OSPF does by default I believe.

[MHM Cisco World · Accepted solution]

RIPv1 and RIPv2 support redistribute connected
the issue is RIPv2 is classless which can advertise the two prefix 

RIPv1 is classful which will advertise only one prefix 
the issue is RIPv1 see one prefix not two 
you can use different class for secondary IP and check again. 

[Richard Burts]

I agree with @David Ruess that RIPv1 is strictly classful in its approach to routing. It would regard

192.183.12.1 255.255.254.0

as invalid (based on the /23 mask) and would not advertise it. RIPv2 relaxes the classful requirements, recognizes the /23 as valid, and advertises the network.

[bijay.swain]

Hi MHM

Thanks for your reply.

I tested with different class  and it did advertised it with default mask