Networking and Connections…
Hey guys, I am back again with another interesting practical i.e. Creating a network Topology Setup in such a way so that System A can ping to two Systems System B and System C but both these systems should not be pinging each other without using any security rule e.g. firewall etc.
Yes you heard it right . NO FIREWALL :)
So let’s get on and solve this challenge.
To solve this challenge we are gonna need the help of routing table. And 3 O.S .— A, B and C
System A
System B
System C
The routing tables of the above systems A,B and C are visible in the above images.
Command used : route -n
For System — A
Step -1 : Giving System A new IP and Netmask.
As you can see in the image below , I have changed the IP and Netmask of System A.
Command used: ifconfig NIC_card_name new_IP/netmask
Step 2: Providing a new range for connectivity within the network.
Here I have updated the routing table by adding the destination of connectivity of this system to the IP range given in the image below.
Command Used: route add -net IP/netmask NIC Card
Now we are done with the configuration of System A …
System B and C
Step 1 : Disable their Connectivity…
As you can observe in the images below, I deleted the rule for having connection with the outside world and within their subnet/ network/IP range. Hence, no connectivity.
Command used : route del -net destination/netmask NIC_Card
System B
System C
Now as you can observe in the images below ,these systems are unable to make connection with each other and system A as the Network is unreachable
System B
System C
Now That their connectivity is down, it’s time for step 2
Step 2: Restricting them to a particular range.
As you can observe in the images below , I have now added another rule in the routing table restricting them ( system B and C ) to a particular range and netmask.
System B
System C
Now we are done with the Configuration of all 3 systems A , B and C.
It’s time to check whether we were successful in achieving the task or not.
System A
As you can observe in the picture above System A is successfully able to ping to both the systems B and C. So we can say A has connectivity with both B and C.
System B
As you can observe in the image above , System B is successfully able to make a connection with System A but not with C. So we can say , B has a connection with A but not with C.
System C
As you can observe in the image above , System C is successfully able to make a connection with System A but not with B. So we can say , C has a connection with A but not with B.
Therefore , We can say that we have successfully created a network Topology Setup in such a way where System A can ping to two Systems System B and System C but both these systems are not able to ping each other and we have achieved this without the use of any security rule e.g. firewall etc. Instead we managed to achieve this with the help of routing table.
Well That was all from my side , hope you found it interesting. Keep learning :)
Arjun Nigam
Signing Off!!!
