RIP network command

[strikeric11]

Hi there I'm reviewing my ccna topics so I created a Lab to refresh my memory.: If the purpose of network command is to 1.) advertise the network covered in network command 2.)send routing protocol(rip) updates to the interface covered in network command.

So here's my problem .If I issue R1#debug ip rip

          R1#RIP: sending  v2 update to 224.0.0.9 via FastEthernet0/0 (172.16.1.2)

          RIP: build update entries

                192.168.1.0/24 via 0.0.0.0, metric 1, tag 0

as you can see R1 does not advertise the 172.16.1.0/24 to the fa0/0 interface. My question is why does it not advertise the 172.16.1.0/24 to the

fa0/0? I did not configured rip to R2 cause it will enable split horizon of R1 due to the fact R2 will advertise the 172.16.1.0/24. Both interface of R1 is in up/up status. I can't recall the reason why can you pls enlighten me. Pls don't tell me that its split horizon issue. Thank you

here's my config

R1#show running-config

Building configuration...

Current configuration : 614 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname R1

!

!

!

!

!

!

!

!

!

!

!

!

!

!

spanning-tree mode pvst

!

!

!

!

interface FastEthernet0/0

ip address 172.16.1.2 255.255.255.252

duplex auto

speed auto

!

interface FastEthernet0/1

ip address 192.168.1.1 255.255.255.0

duplex auto

speed auto

!

interface Vlan1

no ip address

shutdown

!

router rip

version 2

passive-interface FastEthernet0/1

network 172.16.0.0

network 192.168.1.0

no auto-summary

!

ip classless

!

!

!

!

!

!

!

line con 0

line vty 0 4

login

!

!

!

end

R2#show running-config

Building configuration...

Current configuration : 484 bytes

!

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname R2

!

!

!

!

!

!

!

!

!

!

!

!

!

!

spanning-tree mode pvst

!

!

!

!

interface FastEthernet0/0

ip address 172.16.1.1 255.255.255.252

duplex auto

speed auto

!

interface FastEthernet0/1

no ip address

duplex auto

speed auto

shutdown

!

interface Vlan1

no ip address

shutdown

!

ip classless

!

!

!

!

!

!

!

line con 0

line vty 0 4

login

!

!

!

end

[JohnTylerPearce]

router rip

version 2

passive-interface FastEthernet0/1

network 172.16.0.0

network 192.168.1.0

no auto-summary

The problem you are having, is that with the above command, 'passive-interface FastEthernet0/1', you are preventing any route updated going out of Fa0/1 on R2. This is why no routes are being advertised out of Fa0/1.

And split Horizon, will prevent R1 from learning about the route to 172.16.0.0 out of the interface from which it was learned.

With the commands below, you are advertising the 172.16.0.0/30 and 192.168.1.0/24 networks

network 172.16.0.0

network 192.168.1.0

[strikeric11]

Thanks Tyler for the reply. I intentionally put passive interface on R1 fa0/1 cause it's connected to Lan network and no need to send and receive advertisement. Now I've recalled it has something to do with split horizon. And the reason why R1 does not send the 172.16.1.0 to fa0/0 cause it's connected through it. Which means connected routes are also learned which has administrative distance of 0. Thanks

[strikeric11]

"I did not configured rip to R2 cause it will enable split horizon of R1 due to the fact R2 will advertise the 172.16.1.0/24"

Sorry for this quote this is wrong. If I enable rip on R2 with the network 172.16.0.0 command, R2 will not advertise the 172.16.1.0 to R1 cause split horizon will take effect. R2 is connected to 172.16.1.0, just what I said in the previous post that connected routes are also learned. Thanks

[Simon Brooks]

You answered your own question really.  Why would RIP advertise the 172.16.1.0 network out of that interface if its a connected interface (i.e. it has learned of that network in its own connected interface list)

Split horizon says don't advertise a network out of the same link you received it on, in this case we received 172.16.1.0/30 on Fa0/0 so we aren't going to advertise it out of that link!

Also, why would R2 need to know about the 172.16.1.0/30 network when it already has a connected interface.

Enabling RIP on FA0/0 of R2 will not cause an issue, it will just receive the 192.168.1.0/24 routes from R1 and do exactly the same as R1 (i.e. not advertise the 172.16.1.0/30 network out of FA0/0!

"Pls don't tell me that its split horizon issue."

Does this explain anything or are you after a different answer?

Simon

[strikeric11]

Thanks for the reply brooks just what I said in the previous post I'm trying to recall. so please bare with me.But anyway sorry for the inconvenience I've brought to you. Thanks