Question

Explain how an external attacker could attempt to determine what servers are accessible on the internal network, and which servers are blocked by the firewall.

Answer 1

First of all, the attacker will try to send the malicious packet and then broadcast the packet to all the devices present in the infrastructure. The packet will easily pass and affect the machine which do not have firewall in the system. It is always difficult to figure out whether a system is enabled with a firewall or not specially when trying to break from an external network. Only thing that can be done is the attacker has to broadcast the malicious packet to every device in the infrastructure and once the malware entered the device, the attacker will come to know the IP address of that device.