Why ChooseThe Firewall
In terms of computer security, a firewall is a piece of software. This software monitors the network traffic. A firewall has a set of rules which are applied to each packet. The rules decide if a packet can pass, or whether it is discarded. Usually a firewall is placed between a network that is trusted, and one that is less trusted. When a large network needs to be protected.
Network firewalls filter traffic between two or more networks. Firewall appliances may also offer other functionality to the internal network they protect, such as acting as a DHCP or VPN server for that network. Network layer firewalls, also called packet filters, operate at a relatively low level of the TCP/IP protocol stack, not allowing packets to pass through the firewall unless they match the established rule set. Firewalls often have network address translation (NAT) functionality, and the hosts protected behind a firewall commonly have addresses in the private address range.
Firewall Security
It includes controlling physical access to the hardware, as well as protecting against harm that may come via network access, data and code injection.
Firewall & Network
Type of Firewall
An external firewall is placed at the edge of a local or enterprise network, just inside the boundary router that connects to the Internet or some wide area network (WAN). One or more internal firewalls protect the bulk of the enterprise network!Firewall & NetworkPacket-filtering firewalls
It operates at the router and compare each packet received to a set of established criteria (such as allowed IP addresses, packet type, port number, etc.) The Packet Filtering Firewall is one of the most basic firewalls. The first step in protecting internal users from the external network threats is to implement this type of security. The first ever firewalls used were of packet filtering type only. As the trends of network threats started changing, so did the firewall building strategies. .
Firewall & NetworkCircuit-level gateways
It monitor the TCP handshaking going on between the local and remote hosts to determine whether the session being initiated is legitimate — whether the remote system is considered “trusted.” They don’t inspect the packets themselves. Information passed to a remote computer through a circuit-level gateway appears to have originated from the gateway. Circuit-level firewall applications represent the technology of next to first generation. Firewall technology supervises TCP handshaking among packets to confirm a session is genuine
Firewall & NetworkStateful inspection firewalls
It examines each packet, but also keep track of whether or not that packet is part of an established TCP session. This offers more security than either packet filtering or circuit monitoring alone, but exacts a greater toll on network performance.
Firewall & NetworkApplication-level gateways
It combines some of the attributes of packet-filtering firewalls with those of circuit-level gateways. They filter packets not only according to the service for which they are intended (as specified by the destination port), but also by certain other characteristics such as HTTP request string. While application-level gateways provide considerable data security, they can dramatically impact network performance.
Firewall & NetworkMultilayer inspection firewalls
It combines packet filtering with circuit monitoring, while still enabling direct connections between the local and remote hosts, which are transparent to the network. They accomplish this by relying on algorithms to recognize which service is being requested, rather than by simply providing a proxy for each protected service. Multilayer firewalls work by retaining the status (state) assigned to a packet by each firewall component through which it passes on the way up the protocol stack. This gives the user maximum control over which packets are allowed to reach their final destination, but again affects network performance, although generally not so dramatically as proxies do.
