Discuss the differences between the firewalls and the different levels of security they provide.

The firewall allows authorized data to pass, but rejects unauthorized data communication. A network firewall is a defense system that isolates the intranet and the Internet, allowing people to communicate between the intranet and the open Internet. Visitors must first traverse the security lines of the firewall before they can reach the target computer.When there is no firewall, every node in the LAN is exposed to other hosts on the Internet. At this time, the security of the internal network is determined by the sturdiness of each node, and the security is equivalent to the weakest node. After the firewall is used, the firewall will unify the security of the internal network to itself, and the network security will be reinforced on the firewall system instead of being distributed on all nodes of the internal network.
The second video is brief and it listed the main differences between the firewalls and the different levels of security they provide. The packet filtering – stateless firewall is simple to configure, it blocks certain ports and IP addresses that are allowed or not allowed to transfer past the firewall. The stateless firewall is prone to an attack if a malicious packet can find its way into one of the open ports. The packet filtering – stateful inspection adds another layer of security by recognizing if there’s an existing conversation between the IP addresses before it can go past the firewall. The NAT firewall has the ability to mask the internal IP address with the external IP address of the router or the gateway, and if the packet doesn’t have the information of the internal address it won’t get past the firewall because the router or gateway doesn’t know where to send them.