RIP

Lets make all of our router's network databases is same or synchronized and let RIP chooses what better path.

Specifying the network:
1. For each router that want to RIP process routing, configure their directly-connected network just at their classful boundary. No use if you define them at their classless address. Like below:
R1(config)# router rip
R1(config-router)# network 192.168.1.0
R1(config-router)# network 192.168.2.0

Configure RIP's passive interface:
1. For interfaces in each router, define what interface that should be blocked from sending RIP's packet a.k.a don't participate in sending packet of RIP update about network update. So we continue/add our previous config above with below:
R1(config-router)#passive-interface f0/0

But before we add that config/command, we need to show ip protocols, like below:

R1#show ip protocols
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 26 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: rip
Default version control: send version 1, receive any version
  Interface             Send  Recv  Triggered RIP  Key-chain
  FastEthernet0/0       1     2 1  
  Serial0/0/0           1     2 1  
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
    192.168.1.0
    192.168.2.0
Passive Interface(s):
Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.2.2          120      00:00:18
Distance: (default is 120)

And now assign:
R1(config-router)# passive-interface fa0/0


And show ip protocols again, like below:

R1#show ip protocols
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 18 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: rip
Default version control: send version 1, receive any version
  Interface             Send  Recv  Triggered RIP  Key-chain
  Serial0/0/0           1     2 1  
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
    192.168.1.0
    192.168.2.0
Passive Interface(s):
    FastEthernet0/0
Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.2.2          120      00:00:00
Distance: (default is 120)

Notice that now FastEthernet0/0 is gone from interface list (list of interface that participate in RIP routing protocol a.k.a active interfaces).

Watch for automatic-summerization.
This is the hardest part to understand with RIPv1. So watch it.
Discontiguos network means is not using subnets of one major network.
Contiguous networks means is using subnets of one major network.

RIP isn't good/better at discontiguos network.

If your networks is inside/using one same major network of IP address, then RIPv1 is good to go. Like this:
172.16.0.0/19
172.16.32.0/19
172.16.64.0/29
172.16.96.0/29
172.16.128.0/29


But if your networks isn't inside/using one same major network, then RIPv1 is wreck/error/fail. For instance like this:
172.16.0.0/19
172.16.32.0/19
172.16.64.0/19
192.168.1.0/24
192.168.2.0/24

I even made a quiz/contest, who able to make above network work with RIPv1 I will give IDR 100.000.

Or, you can use discontiguous networks, but you need to arrange the placement of those networks carefully. Or, just don't use subnets with RIPv1. What I mean is use classful address, don't do subnetting.

Another solution to RIPv1 is using really different major network, like below:
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.4.0/24
192.168.5.0/24

While, RIPv2 have 2 options, RIPv1 have 1. Poor RIPv1.

Everytime you given a topology that contains:

Ok. Thats it for automatic summerization. Our next guest is propagating default-route.

Propagating default-route

If you have a router that have an internet connection then that router is a what-we-call a boundary-router.

To tell a router to advertises its default-route is simple. Just use "default-information originate" inside the mode of router RIP configuration mode. Like below:
R1(config)# router rip
R1(config-router)# default-information originate