- A wall designed to protect a network or system from unauthorized access.
- Hardware firewalls can be purchased as a stand-alone product typically found in broadband routers.
- Software firewalls are installed on your computer and you can customize it. For example:-
- There are 4 common filtering techniques. 1. Packet Filter : Looks at each packet entering or leaving the network and accepts or rejects based on used rules.
2. Application Gateway : Applies security mechanisms to specific applications FTP(File Transfer Protocol) and Telnet servers.
3. Circuit-level Gateway : Applies security mechanisms when a TCP(Transmission control protocol) or UDP(User Datagram Protocol) connection is established.
4. Proxy Server : Intercepts all messages entering and leaving the network.
