FIREWALL

This post  will familiarize you with Firewall , bypass the firewall and tools to bye pass it.

WHAT IS FIRE WALL?

A hardware device and/or software program which sits between the Internet and the intranet, internet, of an organization

It restricts information that comes to your computer from other computers, giving you more control over the data on your computer and providing a line of defense against people or programs that try to connect to your computer without invitation.

In fact, that’s why its called a firewall. Its job is similar to a physical firewall that keeps a fire from spreading from one area to the next.

what is firewall
what is firewall

Firewall objective

Its main objectives are to filter:
what should come in the intranet (inbound traffic) and
what should come out of the intranet (outbound traffic).

what is firewall
what is firewall

TYPES OF FIREWALL

Packet Filtering Firewall : They are usually part of a router and each packet is compared to a set of criteria before it is forwarded, dropped, or a message is sent to the originator.

what is firewall
what is firewall

Circuit level Gateway : they monitor TCP handshaking between packets to determine whether a requested session is legitimate. Information passed to remote computer through a circuit level gateway appears to have originated from the gateway. On the other hand, they do not filter individual packets.

what is firewall
what is firewall

Application level gateways : also called proxies, are application specific. An application level gateway that is configured to be a web proxy will not allow any ftp, gopher, telnet or other traffic through. They offer a high level of security, but have a significant impact on network performance.

application-level-gateway

 

Stateful Multilayer Firewalls : combine aspects of the other three types of firewalls. They filter packets at the network layer and evaluate contents of  packets at the application layer. They allow direct connection between client and host, and they rely on algorithms to recognize and process application layer data instead of running application specific proxies.

 

Network-performance-firewall

Firewall defense your network using one of two access denial methodologies:

  • may allow all traffic through unless it meets certain criteria, or
  • may deny all traffic unless it meets certain criteria

And Criteria to be configured for  firewall

  • PROTOCOL.
  • DOMAIN NAME.
  • PORTS
  • IP ADDRESS

criteria-for-firewall

So these are four criteria on which your network should be defensed by Anti virus. The next post will be on How to bye pass Firewall