Pingability between systems in Network Topology Setup

Objective
Create a Network Topology Setup such that System A can ping to both System B and System C. Also, both these systems shouldn’t ping to each other unless any security rule like firewall/firewalld is mentioned.
Project Understanding
Prerequisite (For better understanding)
System A → 192.168.56.206
System B → 192.168.56.209
System C → 192.168.56.210
OS Used → RedHat 8
Step 1:
Let’s check if each system is pinging to each other



Step 2:
- Let’s enable ping operation within the firewalld in both System B & System C. First of all firewalld should be enabled on both systems and the command for the same is mentioned below:
systemctl enable firewalld --now
- In order to enable ping operation within the same, it should be added as a rule in firewalld and could be done by using the command below:
firewall-cmd --permanent --add-service=ssh
- Complete firewalld configuration could be obtained using the command mentioned below
firewall-cmd --list-all

Step 3:
After enabling ping operation within firewalld, check if both systems are pinging to each other.


Step 4:
Let’s understand the command that could be used to disable ping operation in both the systems as soon as firewalld is stopped. The command used is mentioned below:
- For System B:
systemctl stop firewalld && iptables -A INPUT -p icmp --icmp-type echo-request -s <System_C_IP_Address> -j DROP
- For System C:
systemctl stop firewalld && iptables -A INPUT -p icmp --icmp-type echo-request -s <System_B_IP_Address> -j DROP
After executing the above mentioned command, both the systems are unable to ping to each other


Step 5:
Let’s check if System A is able to ping to both System B & System C

From the above image, System A is able to ping to both System B & System C even though System B & System C are unable to ping to each other.
Objective Accomplished
Thank You !!!
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