Cannot ping directly connected router ip

[Arie]

Hello,

Have a question. Below find my topology. Both routers have two directly connected subnets in their routing tables. Therefore both PC's on both sides should be able to ping devices placed in that subnets. However that's not the case.

E.G: PC 192.168.40.10 can ping his gw: 192.168.40.1 and can ping 209.165.202.158. Why it cannot ping 209.165.202.129 ???

As router has both subnets as direct PC should be able also to ping 209.165.202.129 at least he can ping 209.165.202.158, so why not .129??

Same situation on other side for other PC.

[Julio E. Moisa]

Hi

Have you enable any routing protocol between the routers to advertise their networks? The routers doesn't know how to reach the network of each others, a routing protocol is required like Rip, Eigrp, Ospf, etc. 

For example:

For testing purposes we can enable OSPF to advertise all the connected networks on each router.

Config for Router 2 (I think it is router id hehe) and Router 3
conf t
router ospf 1
network 0.0.0.0 255.255.255.255 area 0
end

write

Please keep us posted once configured the routers.

:-)

[Arie]

I know that routers have t have information about remot subnets to send packets but i am talking about local direct subnet which is already in his routing table. I know if i would enable routing protocol either rip/eigrp/ospf i will get this work. However it should work without it ! Up router has two direct networks inside his routing table (see below). Therefre PC (192.168.40.10) should be able to ping 209.165.202.158 as it's belong to router's subnet 209.165.202.128 without any additional route/routing protocols.

Router's route table:

192.168.40.0/26 is subnetted, 1 subnets

C 192.168.40.0 is directly connected, FastEthernet0/0

209.165.202.0/27 is subnetted, 1 subnets

C 209.165.202.128 is directly connected, FastEthernet1/0 <-------

[Julio E. Moisa · Accepted solution]

Hi

Yeap but the .129 is configured on the router 3, this router does not know how to reach to the subnet 192.168.40.0/26 because it is not on its routing table, if you execute the show ip route command line. 

On R3 try to ping the host 192.168.40.10:

ping 192.168.40.10
or
ping 192.168.40.10 source fa1/0.

The same case with the other router. Ping is a communication in 2 ways.

:-) 

[Arie]

So the packet from PC will reach .129 (router 3) but Router 3 will drop packet as he doesn't know where 192.168.40.10 is, so either i would add static route to 192.168.40.0 subnet or rip2, eigrp on both routers. Am i correct?

[Julio E. Moisa]

Yeap exactly, you are right. Ping is reciprocal (2 ways). Although we set up the source as the IP of the point to point the router will not have how to reach the remote subnet, a routing protocol will fix this situation.  

Please rate the comment if it was useful

:-)

[Arie]

Your contribution has been granted.

[Julio E. Moisa]

It was a pleasure, if you have any doubts please don't hesitate to contact us.

Have a great day

:-)