Custom Network Topology Setup

Jatin Lodhi
3 min readApr 19, 2021


Welcome to another article , Here I discuss and show you Interesting Networking Concept .

Here I am glad & confident to tell you , you will definitely learn something new from this article . 🔥🔥

Do you think 🤔💭 we Create a network Topology Setup in such a way 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 .

So here we go …….

Pre-requisite * 3 VM ( Virtual Machine )

Q To find How Create a network Topology Setup ❓

In My Case* IP of System -A :-* IP of System -B :-* IP of System -C :-

→ First I will show you all 3 VM are connected each other

System - A is connected to System -B & System -C
  • Here you see that all are connected to each other

Q But our requirement is different

→ First we clean our route table run below mentioned command

route del -net del -net <IP> gw netmask <IP>
  • At that if you want to ping any IP it shows NETWORK IS UNREACHABLE

→ Now our requirement is System B & C Connect to System A

→ For this we have to add some rule which allow that particular IP`s but remember one point here I did`nt use any firewall rule .

If you want to System B & C Connect to System A use mentioned below command in SYSTEM -B & SYSTEM -C

route add -net <IP of system-A> netmask enp0s3

→ Now again check route table

route -n

→ Check SYSTEM -C ping to SYSTEM -B or vice versa .

It shows Network is Unreachable

→ Then ping to System -A

System -A Successfully pinging

ping <IP of System B & C>
It shows Network is Unreachable
ping <IP of System A>
System -A Successfully pinging

Here you can see that System -A Successfully pinging .

* I tried my best to explain as much as possible. Hope You learned Something from here. Feel free to check out my LinkedIn profile and obviously feel free to comment and give feedback also .






Jatin Lodhi

I am an IT Enthusiast, who is passionate about exploring/learn all the latest technologies from research perspective.