Cisco – Why Can’t I Ping the Next Hop Router on a Directly Connected Network?

ciscorouting

I have the following scenario:

  1. I am using two Cisco 1941 routers
  2. Network A connected to Router1 (192.168.10.0/24) (Gigabit connection)
  3. Network C connected to Router 2 (192.168.20.0/24) (Gigabit connection)
  4. Network B connecting Router1 and Router2 (192.168.30.0/30) (Serial connection)
  5. No entries have been added to the routing table (other than what is automatically added for directly connected networks)
  6. There is no gateway of last resort set up.

The difficulty:

  • I can ping from Network A to both interfaces on Router 1 (192.168.10.1, 192.168.30.1)
  • Even though Network B has been automatically added to the routing table on Router 1 as a directly connected network, I cannot ping Router2's interface (192.168.30.2) on Network B from Network A.
  • The only way I can get this to work is by adding the gateway of last resort to Router1.

My question:

Since Network B is a directly connected route on Router 1, why can I only ping (from Network A) Router1's interface on Network B, but I cannot ping Router2's interface on Network B?

Best Answer

why can I only ping (from Network A) Router1's interface on Network B, but I cannot ping Router2's interface on Network B?

Because R2 does not know how to get to NetA. This is the purpose of routing protocols: to allow routers to tell each other about networks they can reach.

If you don't want to run a routing protocol, add a static route on R2:

ip route 192.168.10.0 255.255.255.0 192.168.30.1
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