What are firewalls in network security?
Firewalls in network security
A firewall is a security system that controls the exchange of information in the network and blocks all unauthorized information to maintain a safe connection.
Types of firewalls
Following are the types of firewalls:
- Packet-filtering firewalls
- Proxy firewalls
- Circuit-level firewalls
Packet-filtering firewalls
They filter IP (Internet Protocol) packets based on source-destination IP addresses and ports.
Further packet-filtering firewall is divided into the following types:
- Static packet filtering firewall
- Dynamic packet filtering firewall
- Stateful packet filtering firewall
Proxy firewalls
They inspect and limit the incoming information packets and establish a connection to the source of information. The primary purpose of proxy firewalls is to provide security to the internal networks.
Proxy firewalls are also known as Application Firewalls or Gateway Firewalls.
Circuit-level firewalls
They check the TCP (Transmission Control Protocol) handshake to verify incoming information without wasting time. Using the connection, they provide security between the UDP (User Datagram Protocol) and TCP(Transmission Control Protocol). Usually, these gateways work on the session layer of the OSI (Open System Interconnection) model.
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