Firewall is a kind of security device for computers accessing informations via internet.
Firewall protects the computer and network by restricting the access of outsiders or intruders. It also sets up the criteria that must be met before access to the network or system is allowed to anyone.
Firewall is hardware or software or both that helps protect your system connected on the network from untrusted sites that may contain viruses or other malwares.
A firewall traps inbound and outbound packets, analyses them, and then permits access or discards them. If the incoming packet doesn't meet the criteria set by the firewall then the packet will not be allowed to enter the system.
Features of Firewall
Firewall allows or blocks access to particular website based on set of pre-defined rules.Unwanted traffics can be easily blocked using firewall.
Firewall enhances the security feature of the system connected to the network on the internet.
Firewall protects your laptop or mobile when connecting to internet via public wi-fi such as railway-station or airport free wi-fi.
How firewall works?
Firewall acts as a filter.
In case there is no firewall, all the systems in an organization are easily accessible to anyone with sharp computer skills and knowledge. The person with such skills would break in to the organization system making either FTP connection or Telnet connections and will steal valuable data and informations. Hackers love the network with no firewall at all.
But when the same network is under the umbrella of firewall it is safe. Firewall can be configured with the security rules. These rules serves as checklists for the firewall before it allows or denies access. Any X, Y or Z person would not be easily allowed to enter into the network if they doesnot meet the firewall's criteria.
An organisation can secure every connection with firewall. It may set up a rule like out of 1000's of computers only one or two computers (under high security) will be allowed to make any FTP or Telnet connection with any system outside the organisation. Similarly there can be other rules set up by company based on its requirement.
Firewall gives supreme control over how the systems are used and accessed over network.