The application-level payload of the packet.

Properties of the packets and the protocols are −

Rejected − Not allowed through accompanied by an attempt to inform the source that the packet was rejected.

Dropped − Not allowed through with no indication of failure.

Accepted − Permitted through the firewall.

Packet flowing through a firewall can have one of the following three outcomes − To protect private networks and individual machines, a firewall can be employed to filter incoming or outgoing traffic based on a predefined set of rules known as firewall policies.

Firewalls can be hardware or software-based.

Firewalls can prevent unauthorized use before reaching the servers. It uses a set of rules to determine whether to allow or block a specific network traffic. If one employee makes a mistake and leaves a security hole, hackers can get to the machine and exploit the hole.A firewall is a network security device it is a protective layer for the server that monitors and filters all the incoming and outgoing network traffic. A person who knows what he or she is doing can probe those computers, try to make FTP connections to them, try to make telnet connections to them and so on. Without a firewall in place, all of those hundreds of computers are directly accessible to anyone on the Internet. In addition, the company will have one or more connections to the Internet through something like T1 or T3 lines. The company will therefore have hundreds of computers that all have network cards connecting them together. Let's say that you work at a company with 500 employees. If you have read the article How Web Servers Work, then you know a good bit about how data moves on the Internet, and you can easily see how a firewall helps protect computers inside a large company. If an incoming packet of information is flagged by the filters, it is not allowed through. A firewall is simply a program or hardware device that filters the information coming through the Internet connection into your private network or computer system.

What is firewall in computer