A Network Topology Setup such that System A can ping to two Systems System B and System C, but both these systems cannot ping each other.

This problem can easily be solved using the concept of Routing Tables.

Let us have three systems in the same network:

• System A -> 192.168.0.1
• System B -> 192.168.0.2
• System C-> 192.168.0.3

Add route in Routing table such that A can connect to B and C but B and C can only connect to A.

• Adding Route in System A

• Adding Route in System B

• Adding Route in System C

We can see that:

• System A can Ping to System B and System C.

• System B can Ping to System A only.

• System C can Ping to System A only.

Commands Used are:

• route add -net <ip>
  (To add a route)
• route -n
  (To see all routes)
• ifconfig
  (To see IP)
• ping <ip>
  (To ping some other System)