Author : Purvil

Solution

• A firewall is a device which is used to control the flow of traffic into and out-of network. In other words, it is a security device which installed between two networks, internal network to outside network (more often the internet).

• Based on the rule define in the firewall data will be passed to one network to other network.

• The primary job of a firewall is to secure the inside network from the internet.

• Systems on one side of the firewall are protected from systems on the other side.

• For example:

  • Consider LAN is corporate or our campus network and WAN is internet.

  • If we place firewall between the two networks then it will control the flow of the whole traffic and based on rule define into firewall.

  • It will allow or deny the traffic.Firewalls generally filter traffic based on two methodologies:

• Firewalls generally filter traffic based on two methodologies:

  • A firewall can allow any traffic except what is specified as restricted part. It depends on the type of firewall used, the source, the destination addresses, and the ports.

  • A firewall can deny any traffic that does not meet the specific criteria based on the network layer on which the firewall operates.

• Firewall is the first destination for the traffic coming to your internal network.

• So, anything which comes to your internal network passes through the firewall and any outgoing traffic will also pass through the firewall before leaving your network completely.

• This is the reason that sometimes this type of firewall filter is also called screening routers.

• Firewall types the way a firewall provides greater protection relies on the firewall itself, and on the policies that are configured on it.

• The Following types of firewall are:

  • Packet-Filter Firewall

  • Circuit-Level Gateways

  • Stateful Packet-Inspection (SPI)

  • Proxy Firewall

  • Application Gateways

  • Next-Gen firewalls

  • Software Firewall