RIP network statement

[abbas.ali]

RIP doesn't allow to specifically put network statement unlike ospf and newer verison of EIGRP.

If for example r1's s0 is running rip, and s1 will be running ospf in the future. r1's s0 is connected to another r2.

so r1 config

int s0

ip address 170.1.100.0 255.255.255.0

int s1

ip address 170.1.200.0 255.255.255.0

router rip

network 170.1.0.0

now r8 will have a network entry of 170.1.100.0 which is not rip enable, but because of the class network statement r2 will quietly accept that route.

The passive interface in the topology wouln't work since the nature of the passive in only one way, recieve, but don't advertise.

The only solution I think would be to use distribute list on r2 not to accept the 171.1.100.0 route.

What should be the approach in ccie lab if no instruction are given. I would still filter it regardless of instructions.

[thisisshanky]

What is r8 ?

[abbas.ali]

I meant to say r2, not r8. It was a typo error

[thisisshanky]

Is r2 also enabled with RIP ?

[abbas.ali]

Yes, r2 is running rip with r1.

[thisisshanky]

passive interface on s0 of r1 would prevent r1 from sending any updates to r2, even though r1 would continue to listen to updates on s0.

Is that fine according to the constraints in the lab scenario ?

[abbas.ali]

That is what I did first, but network 170.1.100.0 still showed up on my r2's routing table.

[thisisshanky]

Isnt 170.1.100.0 the network address of link between r1 and r2 (s0 of r1 according to your configuration has this network address). This network would not appear as Rip(R) route but it will appear as connected route. Or are you talking about 170.1.200.0 network appearing on routing table of r2 as RIP route ???

[abbas.ali]

Sorry for the error. It is network 170.1.200.0 showing up on r2. Interface s1 on r1 ip address 170.1.200.1 will be running ospf in the future, so right now is not running any routing protocol, but since I put the statement such as

r1

router rip

network 170.1.0.0

I will see the route 170.1.200.0 no r2 which I don't want to and the only solution I can think of is to filter it out.

Thanks

[thisisshanky]

If you are not allowed to use a distribute list, then I can think of an only alternate way. It works.

Use an offset list on r2 to offset the metric of 170.1.200.0 by 15 hops. which makes the total hops of the network to 16, which means the network is inaccessible. This will make r2 to reject the route and thus prevent the network from being installed on the routing table.

r2(config-router)# offset-list 1 in 15

r2(config)#access-list 1 permit host 170.1.200.0

HTH

[abbas.ali]

Sounds like a good solution because in a lab if I am specifically told to run rip on specific interface, then I don't have any choice, but to use either access-list or your method.

Thanks again

[thisisshanky]

You r welcome!

[lgijssel]

You might also run RIP on r1 without the network statement for net 170.1.0.0.

r2 will still learn the connected route but since r1 does not advertise for 170.1.0.0, r2 will not learn this route.

Regards,

Leo